Garden Culture Magazine UK 17

IN THIS ISSU E OF GA R D EN CU LTU RE : 7 Foreword

46 5 Cool Finds

8 Product Spotlights

51 What Grinds My Gears

12 Indicator Plants

52 Predatory Insects

14 Are Plants Vegetarians?

55 Who’s Growing What Where

18 Oxyfertigation

60 Supercharge Your Flowers

24 Is This Still Good?

68 A Garden on a Tower

31 The Tropism Prism

77 The Best Laid Plans

34 Grow Your Own: Avocados

78 Air Pressure and Plant Growth

36 Unicorns & Basement Jelly

81 Shorties

38 Light Matters Part VI: CMH

It is relatively easy to create a space to grow, whether indoors or out, and provide your new garden with a decent place to live. It is also easy to create a space that is hostile to life, where few plant varieties will thrive in the home provided.

In an indoor setting, some wrong choices can create a plethora of problems. Plant nutrition, pH, EC, CO2 levels, bugs, IR heat, disease, and the worst culprit of all, neglect, all have an influence on the garden. When growing outdoors, weather and pests are but a few of the stresses that a plant has to withstand.

Understanding the underlying reasons for certain plant behaviours can help you prevent them from happening in the first place. In the article “Indicator Plants,” Evan Folds uses the love of lawns as an example of how to read the health of the soil.

“Are Plants Vegetarians?” by Karel Schelfhout and Michiel Panhuysen, co-authors of the Organic Grow Book, examines the differences between animal and vegetal based amino acids and peptides. The Lighting Matters series continues this edition with an in-depth look at Ceramic Metal Halides, one of the newer lighting technologies to hit the market. Nico Hill dissects the photosynthesis equation in “Supercharge Your Flowers,” weighing in on CO2 supplementation. Do you use CO2 supplementation? After you read this, you will want to make the extra effort.

When it comes to gardening, the basics are pretty easy. Getting to the next level takes a bit more work, but let me tell you, it is worth it.

Happy Gardening

Eric

A low frequency, square wave, digital ballast, the Maxibright DAYLIGHT 315W is designed specifically to run Philips CDM 315W lamps at the correct spectral output and provide optimum performance throughout the life of the lamp.

The compact, lightweight design of the DAYLIGHT 315 ballast provides flexibility and ease of installation. Robust, reliable, and built using quality components, this ballast gives ‘More Flower for Less Power!’

End-users have stated that by using two 315W systems together, they typically enjoy increased yields of over 20% when compared to a standard 600W HPS system.

• Specifically designed to run Philips 315W CDM lamps • Low frequency, square wave ballast • Small, lightweight & silent • Soft-start technology • End of lamp life detection • Dynamic frequency control • Short circuit protection • Thermal protection To find your local retailer visit: Maxigrow.com/where-to-buy/

Measuring 40cm in diameter, the MaxiFan Wall fan has three selectable speeds, and oscillating or fixed head options to redirect airflow around the room. The lightweight MaxiFan Wall fan is housed in a durable plastic casing, and comes with a sturdy steel fixing bracket for easy positioning.

Other fans in the MaxiFan range include a Clip fan, Floor fan, and a Pedestal fan.

• Three speed with switch and pull string • Oscillating or fixed position • Steel fixing bracket included • 40cm diameter To find your local retailer visit: Maxigrow.com/where-to-buy/

Spectron Light Science LED Boosters are designed to provide growers with increased light uniformity and spectrum when used with existing HPS lights.

Whilst HPS lights remain the preferred solution for most indoor crops, Spectron LED Boosters have been specially developed to bridge the gaps in performance of spectrum and light uniformity, with the added benefits of lowering power consumption and increasing yield.

HydroGarden.com

Underwriter’s Laboratories tests have found that Par Pro’s new Hyper Arc lamp is the most powerful 1100 watt single-ended HPS grow lamp.

Consistently testing at 2,380 µmol (micromole), the new Hyper Arc is an 1100 watt grow lamp that features a 400 volt arc tube and a TT65 European glass jacket that generates 177,000 lumens.

A remarkable milestone in horticultural lighting, the fact Par Pro has been able to accomplish this in a single-ended E39 lamp design should be great news for the hundreds of thousands of singleended reflectors currently in the field.

The Hyper Arc’s PBAR Flux is even more impressive, 2,688µmol!

“PBAR” refers to Plant Biologically Active Radiation which is

measured from 350 to 800 nm in the light spectrum. This value recognizes that plants have photopigments other than chlorophyll that are sensitive to a wider range of wavelengths than chlorophyll.

For more information visit: www.SunSystemLights.com

Spectron Light Science LED Boosters are designed to provide growers with increased light uniformity and spectrum when used with existing HPS lights. Whilst HPS lights remain the preferred solution for most indoor crops, Spectron LED Boosters have been specially developed to bridge the gaps in performance of spectrum and light uniformity, with the added benefits of lowering power consumption and increasing yield.

HydroGarden.com

HydroGarden Who lesale Supplies are pleased to announce that they are no w an official dis tributor of Gavit Horticultural Lighti a ng in the UK and Ire land.

HydroGarden will be stocking the ful l range of Gavita Horticultural Lighti ng products, includ ing the Pro-Line lighting systems, an d the LEP (Light Emitting Plasma) e-series. They will also be stocking th e Master controller lamps, reflectors, an s, d accessories.

The Mammoth Elite Tents, designed to work with Gavita Lights to optimise lighting conditions for your plants, are another line of prod ucts taken on by Hy droGarden.

that is easy to A digital fan speed controller the fan speed sts adju y set, and automaticall temperature. ired des to maintain the set Controller nt llige Inte The Control Freak tic and plas ust rob is manufactured from be. pro e includes a temperatur

(includes 5m • Temperature controlled temperature probe) ature and min/ • Easy to set - Just dial in temper max fan speeds ns the room • “Fansync” software maintai t precision fan temperature through constan speed control accurate and quieter running • Smooth fan speed control for e adjustment of +/- 1°C • Highly accurate temperatur dle fans of most sizes • High power capacity, will han To find your local retailer visit: -buy/ Maxigrow.com/where-to

A smart strategy for organic growing, BioTabs offers convenience, efficiency, and quality. Organic growing sounds complicated, but is essentially the simplest and purest way to grow. In nature, insects, soil fungi, and soil bacteria break down animal and vegetative residue. Those insects, fungi, and bacteria make up the so-called soil organism. The soil organism breaks down organic material and transforms it into food for plants - a food source for new life.

The primal way of organic growing is based on the use of compost upon which a number

Hyperion white spectrum LED grow lights and drivers now available at HydroGarden.

Manufactured by Plessey, the key specifications of the Hyperion grow lights includes input power of 420 watts, a total light output of 710 micromoles, a broad spe ctrum of 450nm–720nm, and a 120o beam angle, providing a mor e complete spectrum.

The computer designed heat sink is constructed with powder coa ted aluminium alloy, ensuring opt imum heat dissipation without the need for fans.

of strategies have been developed.

BioTabs is an organic fertiliser that uses the force of soil organisms to convert organic material into an ideal plant food. In this way, plants develop strong root systems and are disease-resistant. BioTabs guarantees a fair, full, and very tasty harvest.

More info: BioTabs.nl

The Sunmaster® Compact ballast range is now available from Maxigrow. Sunmaster® ballasts are high quality at an affordable price. With renowned components from Venture Lighting inside, they offer peace of mind and reliability as standard. Silent running with cool operation, Sunmaster® ballasts also provide Genuine Power to your lamps.

• Genuine Quality & Power 250W, 400W, and 600W ballasts • Silent running with cooler operation • Matched digital SmartTM ignite • EC approved Capacitor (PFC) (BS EN 61000-2-3) • Precision wound ballast with grade 2 winding wire • Wall-mountable case with carry handle • 3-year guarantee • Runs sodium or metal halide lamps

Sun System’s new iSUNLIGHT T5 is the first of its kind.

T5 HO fixture, you can easily upgrade your lighting from fluorescent to LED by switching lamps!

Using a

choice for propagation and veg cycles of The iSUNLIGHT T5 LED is a 5,500°K T5 HO replacement LED lamp, a superior HO fluorescent fixture that produces T5 existing your plants. An intelligent LED specifically designed to work with your over 5,100 lumens and consumes only 41 watts of power.

Environmentally friendly, mercury-free grow lights. For complete pricing and product information, check out www.SunlightSupply.com.

To achieve optimal growth performance, having a specific light spectrum is a must. Spectron Light Science has developed two main spectra. The FRPENETRATOR spectrum is the best solution for flowering crops, while the BLUVEGETATOR spectrum is for achieving optimal growth during the vegetative stage. A third product, the SMARTBOOSTER offers both the flowering and vegetative spectrums provided by the other two, which can be alternated to match your crop cycle.

HydroGarden.com

The lawn is a good way to have a conversation about soil indicators. Don’t get me wrong, I’m a “food not lawns” kind of guy; but lawns are everywhere. They take up over 49 million square miles in the United States, or three times more area than the next largest irrigated crop. And despite most falling short, everyone wants the same thing out of a lawn – green grass and no weeds, pests, or disease.

Wanting green grass is understandable. After all, the aesthetic value of a landscape is what most people are after with the lawn. Ironically, grass is one of the most nutritious plants on Earth, supporting many of the roughly 150 species of ruminants as a primary food source. Too bad we don’t have four stomachs like a cow!

A plant is a reflection of the health of its ecosystem, including grass. Even with the best of intentions, humanity does more harm to natural ecosystems than help. In fact, all agriculture is innately a disruptive and manipulative exercise. The modern lawn with its monoculture and reliance on artificial fertilizers and toxic biocides is the epitome of artificial agriculture.

Long-term success in growing healthy grass comes down to perspective. Here is an incomplete list of common lawn issues – fleas, clover, fairy ring, dandelion, crabgrass, moles, mole crickets, spurge, fire ants, dollar spot, purslane, brown patch, red thread, grubs, chinch bugs, slime mold – just to name a few. We can choose to look at these issues as bad luck and attempt to kill them with toxic rescue chemistry, effectively killing almost everything else that we do want as well; or we can decide to seek natural balance and diversity.

In truth, these weeds, pests, and disease are simply indicators of immature soil and a physically, minerally, biologically, and energetically imbalanced ecosystem. Do you see plants in Nature inundated with pests? Do you see “weeds” in the prairie? How about disease in the forest?

If we are convinced that weeds, pests, and disease are a form of contamination, then it would make sense to attempt to try and eradicate them. But if we can come

to the conclusion that Nature is working for us and not against us, then we can generate better results, for less money, and heal the Earth while we are at it.

to get to the root of the issue and enhance the maturity of the soil through mineral balance and microbial diversity. In other words, rather than kill the weeds, strengthen the soil.

Granted, much of the imbalance in the average landscape comes from how we develop property, and it may not be possible to prevent weeds from growing on barren land in a field, or achieve the natural balance of the prairie in our landscapes; but in order to get better results and start operating in a more regenerative fashion, we have to start growing soil, not just plants.

If we start to listen to the landscape and stop telling it how to grow, even before soil testing you can identify deficiencies in the soil based on the type of weeds that are growing - it is that direct. Weeds are mechanisms of deficiency; dandelions grow to regenerate calcium, spurge grows for potassium, clover for nitrogen, etc.

Grass is a perennial crop that establishes itself year over year, whereas weeds are annual plants that grow aggressively and complete their life cycles in one season.

The concept of succession, or the process of change in a species structure of an ecological community over time, is the core of ecological science. The annual weeds are preparing the way for the perennial grass; ironically, weeds want the grass to grow.

The same perspective of balance applies for pests and disease too. Pests do not fly by your neighborhood and just happen to land on your property.

A plant is a They are attracted to unhealthy plants through infrared vibrations, and they reflection of actually cannot digest complete plant the health of proteins. This means that the healthier your plants, the less of a food source they its ecosystem, represent for pests. Just like people, the including grass parallels are life.

Weeds are simply a plant growing in the wrong place.

Despite our collective mania towards having no weeds in our lawn, weeds are medicinal herbs for the soil, just like they are for people. They grow to correct soil structure and fix minerals that are deficient.

So, weeds are not bad luck, they grow for a reason; and they do not come from your neighbor’s yard, as they can stay dormant in the soil for up to 50 years. Rather than trying to kill weeds directly using toxic herbicides, it is more effective

And a disease infecting a plant is simply an organism performing its life cycle without a predator. To fault the pathogen without considering balance and diversity is folly.

It would be like blindly taking pharmaceuticals in order to continue eating a fast food diet.

It is our perspective that drives our actions. Grow soil, not just plants. Bring balance. Begin within. There is strength in diversity. And listen, don’t tell. 3

Growers use many inputs in the garden for healthy crops with strong resistance, without ever questioning their source or the overall effect on the plant. Biostimulants are very useful in the garden to mitigate stress, but have you ever considered whether or not a plant is vegetarian? And, aside from the ethical considerations of meat consumption, why should this matter?

Biostimulants are used both in the soil Each plant creates its own plant-specific smart use of and on leaves as a protection against proteins, and needs the necessary building microorganisms abiotic plant stress, and over the last blocks to do so. They produce some amino and biostimulants few years, growers have rediscovered acids on their own, but by providing them is one of the most their importance. Your grandma additional peptides, a grower generates guarded secrets might have used fermented nettle, more self-production of amino acids by the but today we have a new generation plant. in the world of of biostimulants. These products are modern agriculture researched and developed in labs and Let’s just focus on one of the biostimulants not at kitchen tables like in the old days. we frequently use, a foliar spray containing Their purpose, to adjust and improve the physiological a cocktail of vegetal amino acids, peptides, carbohydrates, and processes of crops, remains the same. vitamins. This recipe makes plants efficiently working ‘engines’ capable of optimal take up and use of the NPK nutrients available Simply put, a biostimulant is a natural product that in the soil. If all physiological processes in a plant functions in the stimulates natural processes in plants. It will optimise their right way, a plant grows like it should grow. It will be strong and metabolism and growth. Different biostimulants work in stress resistant. varying ways, but they all make your plants grow better.

The spray is based on amino acids of vegetal origin, extracted The use of microorganisms, like mycorrhiza fungi or from meal of Fabaceae (leguminosae), a very useful group of plants Trichoderma, is not a new practice for many organic that organic farmers employ as green manure cover crops. To be growers. But the smart use of microorganisms and specific, the foliar spray contains glutamic acid, which stimulates biostimulants is one of the most guarded secrets in the plant development and resistance against abiotic stress, such as world of modern agriculture. environmental stress caused by weather. During the growing season, outdoor plants suffer periods of hot or cold weather, What is in a Biostimulant? too much rain, and sometimes drought. Indoors, abiotic stress Based on a mixture of amino acids, peptides, carbohydrates, can happen when temperatures suddenly change, when they are and vitamins, each ingredient plays a role. Amino acids are too low or too high, and from under or over watering, a dry the building blocks of peptides and proteins which are atmosphere, insufficient light, a wrong pH level, a fertilisation essential for an optimal function of plant cells. Peptides are solution with too much salt, and so on. chains of amino acids that transmit ‘signals’ to plant cells, stimulating their growth. They also favour assimilation Another ingredient in the spray is aspartic acid, which is of the supplied carbohydrates and vitamins by the plant. fundamental in several metabolic processes. The amino acids Vitamins are necessary for an optimal metabolism. enhance nutrient uptake and overall assimilation. Plants stay Peptides and proteins are needed for all kinds of processes. healthy and perform better when using these amino acids.

Amino Acids: Animal vs. Vegetal

Almost all amino acids used by farmers are of animal origin

Let’s admit it, foliar fertilisation or the use of amino acids for biostimulation are not new. So, what‘s so special about an all vegetal spray? We think the answer is part of a wider discussion that questions the role animals play in our food chain. Over the last few years, the conversation includes the inputs in agriculture products.

Almost all amino acids used by farmers are of animal origin.

For the human food supply, animal originated proteins have long been considered as better quality than those from vegetal sources. The same counts for amino acids, the building blocks of proteins.

Animal amino acids are extracted from dead animals, as are some organic fertilisers, like bone or blood meal. Sure, not a single cow is killed for the purpose of obtaining amino acids to biostimulate plants - they are extracted from the leftovers of meat production. But aside from the moral and ethical issues, there are several more good reasons to avoid the use of animal amino acids.

Amino acid extraction from animals present some risks: contamination by BSE (mad cow disease), Salmonella, E. coli, and other animal pathogens. These amino acids may also contain traces of antibiotics, heavy metals, chlorides, and salt.

An even bigger problem that cannot be tackled by laboratory testing - animal based amino acids must be transformed by the plant in order to be assimilated. This causes a loss of energy that annihilates a significant portion of the benefits. Some components of the animal amino acids are not useful for plants at all, like hydroxyproline and hydroxylysine.

Vegetal amino acids do not have any of these problems. Plants immediately recognise them. In agricultural applications, vegetal amino acids can be more useful than animal amino acids when considering the overall benefits. They just fit better.

Many of us love to eat meat, though with the environmental impact of its production in mind, we have each lowered our consumption considerably over the last ten years. In the Netherlands and other European countries, meat consumption is declining. Again, we are not vegetarians, but do try to be conscious about the use of animal products. Without getting principled or dogmatic, using vegetal amino acids in agricultural products seems obviously better, striving for healthy ‘vegetarian’ plants.

Plants use their roots for the uptake of nutrients.

Therefore, roots seem the most logical ‘doors’ to enter plants, but it’s not the only way for plants to get what they need. Consider foliar feeding. Carbon dioxide enters the leaf through tiny openings, the stomata. Using foliar sprays, a grower can fertilize plants through the leaves, because the nutrients enter the plant via the stomata. In this way, the nutrient availability is rapid - like a blood transfusion. Some fertilizers, compost tea, or the biostimulant we describe in this article can be applied on leaves as a spray. 3

Bio Karel Schelfhout and Michiel Panhuysen are the Dutch authors of The Organic Grow Book (2017). This practical handbook (over 500 pages) reveals new gardening techniques and explains the basics of organic growing. Karel, founder of the world famous breeder collective SSSC in the eighties, has been a recognized person in the world of horticulture for almost forty years. He played a prominent role in disseminating cultivation techniques first used in the Netherlands, and subsequently switched to organic growing. Now, he is the owner of Biotabs, organic fertilizers. Michiel is a journalist published in several languages, who specializes in organic and urban gardening, and ultra-running. They work together in several projects.

Oxyfertigation is exactly what it sounds like, the application of oxygen to the nutrient solution that is supplied to the roots at regular intervals to nourish the plant. There is an immediate effect on the uptake of both nutrient and water by the plant when oxygen levels drop too low. Studies performed by various universities1,2,3,4 have shown that by actively increasing the oxygen levels around the root zone, you can increase the shelf life of produce, increase tolerance to salt stress caused by under watering, increase chlorophyll content of leaves (the energy producing cells of the plants), increase nutrient uptake, and prevent root disease.

Let’s first take a look at what oxygen is. Oxygen, a colourless, odourless gaseous element, which forms an important part of many organic compounds in plants. It is the most abundant element in the earth’s crust, and makes up 28% of the atmosphere. Without it, aerobic respiration (the way cells make energy) would not happen, which would be a disaster for everything living.

Oxygen is not very fussy about what it will react with, and will react with just about every element to form oxides. In its pure state, oxygen is usually found in pairs (O2 or dioxygen), but a more reactive form is also found, where 3 oxygens bond (O3), and is known as ozone. You may already be familiar with this, for sterilization and odour control purposes. Ozone can be toxic and cause damage to your plants due to its high reactivity.

Having oxygen around the root zone is very important and beneficial, as it is involved in the exchange of the negatively charged nutrients (anions), such as phosphate, sulphate, and nitrate.

The oxygen facilitates the uptake and excretion of these essential nutrients. It is the concentration of dissolved gaseous oxygen (DO) in your nutrient solution and media that is of greatest interest. This refers to the oxygen that is NOT part of a compound, and is described as free.

So, this is not the oxygen that forms part of the water molecules (H 2O) - it is the free dioxygen (O2) I spoke about earlier, floating around. If the levels of dissolved oxygen are too high or low, it can have detrimental effects on your plants.

Temperature also has a big effect on the DO concentration, as the solubility of oxygen decreases with increased temperature. The temperature of the solution is a big dictator to the amount of DO the water can hold. An easy way to prevent these issues is to include air stones that pump fresh air through the solution - the breaking of the surface is what allows the oxygen to dissolve into the solution.

Nutrient chillers are a good idea in very warm rooms to maintain a solution temperature between 2022°C (68-72°F). This also helps to reduce the rate of multiplication of microbes, and algae growth, that will all use up valuable oxygen. Circulation pumps in tanks also help to prevent stagnation and increase the DO of the solution. Generally, the nasty microbes (the pathogens: pythium and phytophthora) tend not to like oxygen, and thrive in poorly oxygenated, warm solutions. The key is to keep your solution cool and oxygenated.

Having oxygen around the root zone is very important and beneficial, as it is involved in the exchange of the negatively charged nutrients

Low concentrations of DO can be caused by overwatering, which in turn, results in waterlogging of the media and the root zone. Plants will start to wilt, due to water stress, which can lead to more serious problems - such as inhibited root growth, blossom end rot, and root rot. Leaving solutions undisturbed in buckets and tanks will allow them to stagnate and fermentation to start, as microbes begin to multiply and respire, using up valuable dissolved oxygen.

Both the Biological/Biochemical Oxygen Demand (BOD) and the Chemical Oxygen Demand (COD) of the system, solution, and the media affect the rate at which DO is used up.

BOD is described as the amount of dissolved oxygen needed by living things to break down organic material (carbon-based compounds such as sugars and biofilms) in a specified water sample, over a certain amount of time at a given temperature. The COD is similar, and in the simplest definition, is the amount of oxygen needed for certain chemical reactions to take place.

Systems with high BOD and COD will reduce the dissolved oxygen concentration faster than one

free oxygen for the plant to utilize as and when it needs it

with lower values. So, to put this into context of what we are doing‌ if you are running pure hydroponics, using only mineral nutrients with no biologicals, no root stimulators, and no brown carbonbased solutions, there is a reduced risk of fermentation, algae, and biofilm formation in the tanks. This means less of the free oxygen is used up, and thus a reduced BOD of the system. This leaves the free oxygen for the plant to utilize as and when it is needed. However, as with everything, there is a balance required, and running systems this way brings its own problems.

So, what is perfect for plants? What is high? What is low? What is toxic?

The recommended concentration of dissolved oxygen is 6-10 mg/L for plants to thrive. A low level would be around 2 mg/L and below. Normal, or what is described as ambient, would be 5-8 mg/L. A high concentration of oxygen with no detrimental effect on the plant would be 30 mg/L, whereas above 40 mg/L stunted root growth and decreased yields are seen.

You now know what concentrations you are aiming for, so you just need to measure it. This can be done with handheld or lab bench meters. However, they can be

little erratic, and a reliable one is quite often expensive. They look very similar to a pH or CF meter, but work with specifically designed electrodes.

But do you really need to measure this?

If you are running a large operation, where access to and visibility of the root zone is limited, causing problems such as water pooling to occur on trays - I would recommend it, as this could prevent root rot from taking over. It can be a double-edged sword, in the fact that it is just another parameter to worry about! If you are aerating your solution 24 hours a day, there should be no real need, unless you are adding extra oxygen by artificial means.

So, you are still not happy with the amount of oxygen in your system, and waterlogging is occurring and causing root rot, or you have read that oxidative stress to the plant can be beneficial? What? Stressing my plant out can be a good thing? Well, this is a whole different story for another day. But in one word... yes, a little stress can help to increase the strength of your plant.

Another method of increasing the dissolved oxygen is using hydrogen peroxide, also known as Oxy+, H 2O2 , and liquid oxygen - to name but a few. It is a very unstable form of water, which wants to release the

extra oxygen as O-, a negatively charged single oxygen, looking to attach itself to something positive and oxide it. The Oattacks anything carbon-based, reducing the BOD. This attacking of everything is one of its powers when it comes to root rot, but unfortunately it is not selective in what it attacks, and will completely sterilize your system. It is also important to follow the instructions, as overdoing it will result in damage to your plants.

The most recent method for increasing oxygen in solutions involves electrolysis

Another drawback is the instability of hydrogen peroxide, as within 24 hours the concentration has halved, and therefore does not seem cost-effective to add it as an oxygenator. But the recent development of

a stabilized form of hydrogen peroxide using silver helps to slow down the release of oxygen, making it active for a longer period of time. Calcium-based stabilized hydrogen peroxides have also been used, however, calcium being calcium, precipitation can occur when used with heavy sulphate and phosphate fertilizers.

The most recent method for increasing oxygen in solutions involves electrolysis - a special machine that passes an electrical current through the solution.

This separates the hydrogen from the oxygen in the water, thus increasing the free oxygen in the solution.

These types of machines have been shown to increase the dissolved oxygen by 50% more than a traditional air stone. The downside is the initial cost compared to the air stone method.

So, now you know what and why oxyfertigation can help to supercharge your garden! 3

I’ve worked for a fertiliser manufacturer for over ten years, and few days go by without receiving a phone call from someone asking if their bottle or bag of nutrients is still good to use. They rarely remember how long ago the product was purchased, and if we’re lucky, the label is still in good enough shape to know what it is. Smart companies will have a lot number from each batch printed on the bottle, making product and date determination substantially easier. Each time I field a call of this nature, I find myself giving a small tutorial on proper nutrient storage, and how to identify if a product has gone bad or spoiled.

Over time, I’ve come to realise that the average gardener doesn’t have the experience or general knowledge of how to make such a determination. If I can do anything to make a meaningful and positive contribution to the wonderful world we live in, it would be to write a piece on this very subject. Well, here we go.

LIQUID INORGANIC AND SYNTHETIC FERTILISERS POSE THE LEAST CHALLENGES

Inorganic Liquid inorganic and synthetic fertilisers pose the least challenges when it comes to product longevity. When stored in the proper conditions, in a dry environment with constant temperatures between 50-80°F (1027°C), they can stay in usable condition for an almost indefinite amount of time. In these circumstances, the soluble salts should remain in solution without any issues, as long as the formulation is stable.

Avoid freezing temperatures. Concentrated inorganic liquids will freeze at a lower point than water, below 20°F (-7°C) because of the dissolved mineral compositions. If they do freeze, the solubility of the minerals can be compromised, and crystalline structures will usually form within the bottle, having a detrimental effect on the formulation that can lead to inconsistencies in the mineral nutrient composition. It is usually best to dispose of the product according to the manufacturer’s Safety Data Sheet (SDS) and local or state regulations.

Avoid this loss by keeping it in a temperature controlled area. Storing the fertiliser outdoors or in an uninsulated shed is not recommended.

Inorganic and synthetic water-soluble granular fertiliser mixes are relatively easy to keep in optimal condition and can have a nearly indefinite lifespan. The main environmental condition to avoid is high humidity. Due to their highly water-soluble nature, granular mineral fertilisers will begin to solubilize in the presence of water vapour in the air. The higher the relative humidity, the faster the product melts into a gooey glob, rendering it void of any reasonable use.

In cold temps, moisture in the air and a temperature below freezing can cause crystalline structures to form if the fertiliser has solubilized, compromising the quality. Water-soluble inorganic nutrients need to be kept as dry as possible, at all times. If the original packaging is not re-sealable, it is a good idea to transfer it into a different container. Just make sure to save the label for future reference.

Organic Organic plant food presents a different set of shelf and storage life challenges. Most certified liquid organic products - like fish emulsions, liquid seabird or bat guanos, and seaweed extracts - are not allowed to contain chemical preservatives. Instead, the manufacturers can use small amounts of phosphoric acid to stabilise the product by dropping the pH to 3.0 or lower: helping to keep the biological components inactive. When they do become active, the product’s stability is min-

imised to the point where bacterial and fungal growth can occur. This growth is usually accompanied by an off-gassing that can cause the bottle to balloon - and sometimes, even explode at the seams.

bilisation over a longer range of time and conditions.

Even so, these products should be treated and stored in the same fashion as true organics to ensure their maximum storage life.

In a retail setting, where the temperatures remain around 70°F (21°C), and the products are away from direct sunlight, organic liquid fertilisers usually stay stable up to five years - sometimes longer. It’s when the product’s seal is broken that the shelf life dramatically decreases. Once fresh air is introduced into the bottle, the effectiveness of the stabilisation process can begin to erode. To prolong the storage life of an opened bottle for as long as possible, always store the product in a relatively cool area, void of direct sunlight. Heat and intense sunlight are commonly the biggest reasons why organic liquid plant nutrients go bad. Also, do not ever allow these types of product to freeze. Freezing will ruin the composition and solubility of the mixture.

Granular or dry organic fertilisers such as bone meal, composted manures, and plant-derived meal products (like alfalfa or neem seed meal) tend to have a much longer shelf and storage life.

These products undergo one or more treatments to preserve their integrity for long periods of time. They can be heated, steamed, rinsed and dried, composted, and dehydrated to remove possible pathogens and remaining moisture. The result is a consistently dry product that has minimal biological activity. However, the introduction of moisture will re-activate the microorganisms present, and they will begin to grow and, in turn, degrade the product.

FOR BEST RESULTS, STORE MICROBIAL INOCULANTS PROPERLY

If an organic product does become active in the bottle and begins off-gassing or ballooning, it doesn’t directly mean that it has gone bad in the sense that it cannot be used. In this case, slowly remove the cap and carefully inspect the product. If there is visibly noticeable fungal growth, I would advise not using the product, because there is no clear way of knowing if the fungi will be beneficial or detrimental to plant and root growth.

Likewise, if the smell is abnormal or rancid, it is best to replace it and properly dispose of the bad product.

Liquid products that contain both organic and inorganic ingredients usually don’t meet organic standards and will often have a chemical preservative to maintain sta-

Granular or dry organics should always be kept in a tightly sealed container or bag, away from any possible interaction with water. As long as these products stay dry, changes in temperature should have little effect on their quality. Regardless, it is always good practice to avoid extreme heat or cold when storing any fertiliser.

Microbials Microbial inoculants are by far the most sensitive to the environment in which they are stored. These products contain living spores of beneficial bacteria and/or fungi that can be easily harmed or destroyed. It is important to avoid temperatures over 80°F (27°C). Warm temperatures can activate the product while still inside the bottle, and excessive heat can cook the tiny spores, rendering them useless to the plant or soil.

Some companies add organic materials into their microbial blends. This makes for a pretty impressive product, but if the spores do become active within the bottle, the organic components act directly as a food source for the microorganisms and the product will surely go bad in a short time. Always store these products in an area with temperatures between 60-80°F (15-27°C), and be sure to keep the lid on tight.

Granular water-soluble microbial inoculants should be stored in sealed bags or containers in a cool and dry environment. Moisture will not only start to solubilize the material, but it will also activate the microorganism spores and, if there are other organic materials in the mix, they will begin to feed on them. As long as these products stay dry and are not stored in temperatures below 40°F (5°C), since cold can harm the spores, they will maintain their quality for quite some time.

Spore viability naturally diminishes over time. Although proper storage helps to ensure longer viability, some state regulatory agencies require manufacturers to include an expiration date on the label, typically a 2-year period. Although still a developing field of study, regulatory labs are currently working on developing the best methods to enumerate healthy viable spores with the goals of creating guidelines for product testing and to ensure the consumer that the contents match the list on the label. Generally, after a couple of years, many of these types of products will still have viable spores, even if they are lower than the numbers on the label.

For best results, store microbial inoculants properly and use them within two years.

Having to dispose of nutrients and supplements gone bad when it was easily avoidable is a foolish waste of money. Paying extra attention to proper storage conditions is a small step that can go a long way in maintaining a fertiliser’s quality over time. 3

Defined as a plant’s growth response to external stimulation, tropism falls into two groups - positive and negative.

Positive tropism affects the plant’s growth and movement towards a stimulus, and negative tropism affects the plant’s growth and movement away from a stimulus. If you understand the tropisms and movements of plants, then you can control them, resulting in bigger and better yields.

Positive and negative effects are found in all the corners of the tropism prisms: Phototropism, Gravitropism, Hydrotropism, Heliotropism, Chemotropism, and Thigmotropism.

Positive Phototropism When under a light source, you will see that plants grow towards the light. Move the light to the right or left and the plant will follow, in time. How do they know where the light is?

How do they move towards it?

Most plants detect a light source at the tip of the shoots.

Phototropism is a result of auxin (a natural plant growth regulator) that encourages the elongation of cells behind the apical meristems.

Dependent on the plant type, there is a dominant stem where the auxins are more abundant, called the apical dominant stem, and at the top of this is the apical bud.

The more abundant that the auxins are in the dominant stem, then the bigger part this plays in defining plant shape. Christmas trees have an auxin-abundant apical bud making the main stem clearly dominant with the branches growing from there, creating the overall tall and pointy shape like a rocket. An oak tree, however, has much lower levels of auxin in the main stem, and thus the shape is more rounded like a lollypop.

If the apical dominant bud is removed, the auxin is distributed to the lower stems, making them more dominant. This is called “topping” and is used to maximize the number of fruit-yielding stems. It is a very effective way of making one plant yield huge fruits in larger numbers as it encourages horizontal growth as opposed to vertical growth.

So, how do plants grow towards the light and have the ability to move? The answer lies in the shadows of the plant.

Phototropic effects are used in hydroponics to lengthen plants by using light sources with different light spectrums to encourage growth. One is known as “stretching” where a certain flowering light spectrum is positioned too far away from the plant.

Phototropic effects are also used to “stunt” growth by using a certain vegetative spectrum of light and keeping it very close to the plant.

Negative Phototropism This is most clearly seen in the germination stage with the roots growing away from the light. Even seeds germinating on the top of the medium will burrow their roots into the darkness of the soil.

Roots are very sensitive to auxin, and the auxin within the roots act in a very different way. This effect inhibits the cell, elongating growth. Thus, the roots will grow away from the light.

“Air pruning” a plant’s roots is essentially using negative phototropism to encourage the root growth back into the plant’s pot, increasing the overall growth and strength of the roots.

Positive Gravitropism This is the movement of the roots growing “down” due to gravitational pull. The cells and the nucleus of the cells within the root’s growing tip are sensitive to the pull of gravitation. These cells are found in largest numbers within the taproot of the plant, which grows mainly downward, giving the upper part of the plant its main anchor points to the ground.

The auxins elongate the cells on the shaded side of the stem, allowing it to bend, so that growth is towards the light source.

The auxin in the roots works to inhibit the growth of the cells closest to the gravitation field, hence the roots’ growth is always towards the strongest point of gravity.

Negative Gravitropism This is the growth movement away from the force of gravity. If you lay a potted plant on its side in a light-proof box, the roots would turn towards the pull of gravity (positive gravitropism), and the stem would turn up and grow away from the gravitational pull, (negative gravitropism) growing as straight as it could vertically without a light source, which wouldn’t be very long.

It can cause the roots to grow away from the pull of the Earth’s gravitational field. On a typical plant these roots grow underground, away from the light. They grow out of the secondary roots and utilize the medium that the plant is growing in.

Positive Hydrotropism Normally in the roots, this is the growth towards a water or nutrient reservoir.

Negative Hydrotropism This is the effect of a plant’s growth away from a source of water. For plants to effectively feed, the conditions need to be right for the roots. They will actively grow away from a water or nutrient source, which may have a negative effect, like a saltwater river.

Positive Thigmotropism Here we have movement and growth towards a physical stimulus. Creeping and vining plants can climb as they move and change direction of growth positively and negatively in response to the plant physically touching an object.

The plant moves auxins away from the “touching” area of its stem, which elongate the cells on the far side (non-touching

part of the plant). This makes the touching part of the plant wrap around any object that it comes in contact with. The more the stem is pushed onto the surface of the physical stimulus, the more auxin it will send to the non-touching part, and the faster it will grow around the object.

Negative Thigmotropism Mostly found in a plant’s roots system, this is the negative growth effect of physical touch. Roots will generally grow around or away from a physical object alien to its environment, moving toward what they are seeking (fertile medium).

This allows the roots to grow through and around any object with minimum resistance. So strong is the effect of negative thigmotropism, it can override the gravitropic effects of a root system. Imagine a concrete slab under a plant’s root path. The roots either grow away from or around the immovable slab, taking the path of least resistance.

Positive Chemotropism This is the plant’s growth movement towards a chemical stimulus.

Negative Chemotropism Here we have a protective plant growth movement. Plants’ roots actively grow away from any chemical stimulus that could have a negative effect on the plant.

Positive Heliotropism and Paraheliotropism Heliotropism (or plant solar tracking) is normally found in flower heads and the stem just below the head. Paraheliotropism is normally found in the leaves and the stem just below the leaf blades. Some plants, like sunflowers, are so effective at heliotropism movement that the flower heads at the peak of bloom actually track the sun as the day passes. This movement is so strong that you could actually watch them move as the sun passes over.

Negative Heliotropism and Paraheliotropism The negative effect of these is shown in a drought period. The plants actively turn the flower heads and leaf blades away from the light source to slow the whole mechanism of the plant down to save water and nutrients.

I hope you found this article to have a positive knowledge-tropic effect on your gardening, whether that is indoors or outdoors. 3

Avocados have never been so popular as right now.

Seen as somewhat of a super food, they are turning up in everything from conventional dips to sandwiches and salads, and even more unusual food choices, including smoothies and desserts.

They contain an abundance of vitamins and minerals, including potassium (twice as much as an average banana) which helps control blood pressure, lutein which is good for your eyes, and folate which can help in pregnancy to prevent congenital disabilities and neural tube defects, as well as being thought to possibly prevent strokes. They are a good source of B vitamins, which helps fight off disease and infection, and also give you vitamins A, C, E, and K - plus natural plant chemicals that may help prevent cancer.

It doesn’t stop there. They are low in sugar, high in fibre, and also contain the highest levels of protein of any fruit - protein that can help to build muscle and burn fat.

Avocados are one of the richest sources of monounsaturated fats in the world, and they contain quite high levels of these fats. This is still a plus point, however, as this is a “good” fat, one shown to reverse insulin resistance, regulate blood sugar levels, and can help to lower bad cholesterol. It can even be applied to the skin as a moisturiser!

So, it’s no surprise that the avocado is the fruit of choice for many who are actively dieting, working out, or just living a health-focused lifestyle.

Supermarkets are well aware of this and exploit the popularity of this fruit with high pricing and extravagant, unnecessary packaging. Wouldn’t it be great if you could simply grow these “super fruits” yourself, and with minimum fuss? Well, it is possible to do, but don’t turn your back on the supermarkets just yet, as it is not without its challenges, and it can take years for an avocado tree to finally bear fruit! Like a challenge?

Fancy giving it a go? Here’s how:

1. Take the large seed, known as the “pit,” from the center of your avocado. Give it a good rinse, and then dry it off, so it is not slippery.

2. Take 3 or 4 cocktail sticks or toothpicks, and pierce the seed with them. The seed’s pointy end needs to face upward.

3. Suspend the seed over a glass of water by resting the toothpicks on the glass. You want the water covering about an inch (2.5 cm) of the seed.

4. Place it in a warm location, and add water regularly to keep the level constant.

5. Look for roots and a stem to develop within 2-6 weeks. Not all seeds will germinate, so if after 6 weeks there is still nothing happening, then start over with a new seed.

6. When the stem is about 6 inches (15 cm) long, trim it in half. Once it grows and leafs again, transfer the seed to a pot (root end down), covering it all with loose, sandy soil - but leaving the pointy end sticking out.

7. Place the pot in a spot that naturally receives a healthy dose of direct sunlight to encourage growth. Make sure to water lightly and often. Continue with this until the seed begins to split.

8. Once the seed splits, transfer to a 5 inch (12 cm) diameter pot, and cover it completely with soil. Give it a proper watering, allow the pot to drain, and leave it in a dark, warm place. Remember to water as necessary.

9. When you see a shoot sprout, move the pot back to your sunny spot, and continue to water lightly and frequently.

10. Encourage full structured plant growth by topping the new leaves at the highest vertical point of the plant whenever the stems grow another 6 inches (15 cm).

This will make it grow bushy and full.

11. When the plant has filled the pot with roots to capacity, transplant it into as large a pot as possible, as this will be its ‘forever home.’ Make sure to use a rich, peat-free compost, and top up with fresh each year!

That’s it… now the wait begins.

Indoor plants do not usually live as long as the avocado plant needs to bear fruit. Give it its best chance by keeping it in a humid, well-lit environment, such as a greenhouse or an indoor grow room.

Bringing an avocado to fruit indoors is a challenge that many gardeners enjoy taking on, nurturing and watching it grow with hopes that one day they will experience the real achievement of seeing their tree produce some delicious, super nutrient-packed avocados.

It’s a long-term commitment, and one that’s worthwhile, not only for the bragging rights, but also for the potential health benefits. 3

When it comes to my indoor garden, there is no plant that can’t be grown. Well, maybe it can’t, but I will try anyway. Some new plant-growing experiments, like ginger and turmeric, turn out better than anticipated and are now a constant in the garden. Others take a long, long time to bear fruit.

Case in point, grapes. Just over three years ago, I bought two grape vines at the summer market. I planted them indoors in 12-litre pots in a soil-sand mix that was recommended by the lady who sold them. I gave them a nice spot in the grow room and off they went. They produced lots of green vines and seemed to be very healthy.

IT PROBABLY WASN’T WATERED FOR TWO MONTHS...

About a year later, one of the happy vines got transplanted into an Autopot, and things started to explode. The vine loved the coco and bottom feeding. It grew and grew and grew. When I would go away for a week-long trip, I inevitably came back to a jungle of vines. They seemed to attack neighbouring plants like a ravenous boa constrictor.

Cutting them back was a regular job, one that my other plants relied on.

Months passed, yet this prolific vine never created a single grape. I honestly know nothing about growing grapes, and I couldn’t find anything on growing them indoors. Grapes require time, and young plants can take years. My grow room is not very big and having to continuously care for plants that give you nothing in the short term is not very productive, or gratifying, to say the least. So, I decided to

split up the pair - one moved outside, and one stayed put downstairs.

To be honest, the one outside was neglected. It remained in an 8-litre pot most of the summer - getting its moisture from the rain and not getting fertilised nearly enough. Despite my mistreatment, the plant still grew and looked great. Until that fateful night in July, when some mysterious creature ate the entire plant. I was pretty confused at first, then a bit upset, but I got over it quickly. It wasn’t long before the nub of a plant outside started growing again. It never amounted to much, but it did survive the attack.

Downstairs was another story. That plant kept growing like crazy, no grapes in sight. At one point, I just gave up and decided that it too, was going outside. I cut it back, almost completely, and removed the plant from the room. I must have been busy or just didn’t get around to it, but I never took it outside. It had been placed just outside the grow room in the equipment and general storage area, and that’s where it stayed for about two months, unwatered. I waited too long, and it was now Fall, nights were getting cold, and it was getting too risky to transplant outdoors.

So, I decided to just stick it back into the Autopot system. Sure enough, it started growing. Little green nubs indicating life, and in no time, it was green again. But now it grew differently, slower; then it stopped growing. I was ready to give up on my aspirations of growing grapes in the basement. Maybe not kill the plant, but it was going to lose its spot under the warm, bright artificial lights.

I HONESTLY KNOW NOTHING ABOUT GROWING GRAPES

Then it happened, as I was taking the plant out, I found three little branches - each with a triangular set of small white flowers! These had to be grapes.

What to do? I brushed the flowers with a paint brush, rang my chimes, and tried all my tricks to ensure pollination would occur. I had waited three years for this. It wasn’t long before there was signs of little grapey life. I did it... by accident, but I did it.

Those grapes did grow. Unfortunately, I’m not sure exactly how I did it, but those months of neglect seemed to help.

It took about nine weeks to grow into a beautiful bunch of purple grapes.

What type, you ask? I’m not sure.

They are similar to Concord - maybe they are Concord - that’s how they look and taste, with that nutrient, under those lights, and so on. Either way, I harvested them all and made grape jelly. I have never heard of, or tasted, basement jelly anywhere else. It was very good. Different than any jelly or jam I had ever tasted. Sometimes I look back at those jelly-eating days and wonder if I will ever taste again, the deliciousness that is basement jelly. 3

I’m sure you have heard about a new type of lamp that is creating waves in the grow community: CMH, CDM or LEC!!?? So what is this and how relevant is it? Is this the new step in plant lighting? Where did it originate from and what are the benefits?

What’s in a Name

Why Evolve from MH

CMH stands for Ceramic Metal Halide, a relatively new type of High-Intensity Discharge (HID) lamp, like HPS and Metal Halide. It’s a little bit of both, but we will touch on this later. Developed in the early 80’s, Philips made it a commercially successful product in the 90’s, when it launched a line of CMH lamps under their product family name “CDM.” So, that’s the first ”alternative name” you will see pop-up.

Metal Halide (MH) lamps have always been popular in the grow light industry because of their wide spectrum, including much more blue light than HPS lamps. Instead of sodium, MH lamps contain, as the name implies, metal halides, or metal salts. When excited in a plasma these components start emitting a bright light. The spectrum depends on the composition of the salts.

To understand why CMH lamps are a step forward we need to know a few distinct disadvantages of MH first: 1. Efficacy Though they look quite bright to us, in terms of plant light (PAR) MH lamps are not so efficient. Think 2540% less efficient than HPS. 2. Color stability MH lamps shift in colour during their lifetime.

3. Light maintenance MH lamps lose up to 20% over the first 2000 hours and an average loss of more than 8% per 1000 hours over their lifetime is no exception. Compare this to high-quality DE HPS lights which lose less than 3% per 5000 hours of operation.

4. UV emittance They emit a lot of UltraViolet radiation, including UVC. According to the FDA’s latest report, “UV Burns From MH Lighting Remains a Public Health Concern,” one broken bulb can emit an entire day’s exposure to the sun in just eight minutes. In most cases, regulations require MH lamps to be used behind a glass filter, to filter out the UV radiation but also for safety. See point 5.

Sunlight Supply, a hydroponics supplier and lighting manufacturer, introduced a fixture with that lamp, registering the trade name “LEC” - Light Emitting Ceramic.

It has a very similar structure as LED (Light Emitting Diode) and LEP (Light Emitting Plasma), and it aims to compete with these. The only flaw in the name is that the ceramic material doesn’t actually emit any light, but that’s a detail.

So, there is the second brand name of CMH.

5. Not always suitable for open fixture Most MH lamps are not suitable for installation in a fixture without a glass filter. There are two reasons for this - UV emittance, as seen in point 4, and the behaviour of the arc tube, if it fails, is a safety issue.

Over time the quartz glass arc tube of an MH lamp corrodes from the extremely aggressive MH salts inside the lamp, and cause discoloration of the arc tube, diminishing the output. In some cases, ignition of a warm lamp or a deteriorated arc tube can lead to an explosion of the arc tube. The pressure inside an MH lamp is much higher than the pressure inside an HPS lamp and the temperature inside can reach over 6000° Kelvin. An explosion creating super hot particles can even be a cause of fire.

6. There are few MH lamps suitable for open fixtures, ones that have special preventive measures to contain an arc tube explosion, such as a double outer jacket or an extra glass shroud around the arc tube, are suitable for open reflector. Look for the ANSI designation /O (suitable for open fixtures).

The National Electrical Code (NEC) and UL prohibit other MH lamps to be used in open fixtures - you are in violation of the installation code if you do so, and damages as a result of such an installation are not covered by your insurance.

Images: /O versus /E MH lamps (source: Venture Lighting) - A rupture of the outer glass balloon will not automatically extinguish the lamp. As the glass balloon is responsible for filtering out all dangerous UV light, a dangerous situation will result. Accidents causing broken outer balloons in public spaces, such as stadiums and large halls, have caused regulations to become more strict. Lamps suitable for open fixtures, therefore, have protection to prevent this from happening, usually through a double glass balloon.

So, What is Ceramic Metal Halide?

The only real difference between MH and CMH is the C which stands for “Ceramic.” It refers to the arc tube material used in a CMH lamp, which is a ceramic material, polycrystalline alumina, the same material used for HPS lamps. More stable than quartz glass (resistive to the aggressive salts), it can withstand much higher temperatures, ones at which quartz glass would almost start to melt. By using a higher temperature inside the arc tube the efficiency, colour stability, and light maintenance can be greatly improved. I do say “can,” because not all CMH are much more efficient or have a much better light maintenance.

It was only in the early 2000s that manufacturers were able to produce a lamp with a higher wattage than 150W. The first commercial “medium wattage” lamps (250W and 400W), were launched by Philips under the brand MasterColor Ceramic Metal Halide HPS-Retro White. They were meant to replace 400W HPS lamps in magnetic low-frequency ballasts in general lighting, and provide a much better quality light. Hence the HPS-Retro (HPS retrofit). The wire around the ceramic arc tube was to prevent fatal explosions, and so it passed the /O certification for open fixtures. With the introduction of the new generation, these versions have been phased out.

A Closer Look at Spectrum Note the difference in the red spectrum between the 930 and the Agro:

Renewed Interest The CMH lamp that created all this new interest is the CDM 315 lamp from Philips, in particular, the CDM Elite 315 Agro. The CDM 315 already was around for a while when Philips created a new spectrum, adding more red light than the standard 3000 Kelvin lamp, producing a sort of purple glow. It also added efficiency, reaching 1.9 µmol s-1 per Watt initially with a light maintenance of about 94% per 5000 hours. There are two more versions of this lamp, developed and suitable for general lighting: The regular 942, with a 4200K colour temperature, and the 930 at 3000K, but at a lower efficiency in the PAR spectrum. Make sure you get the special Agro lamp if it is efficiency you want The standard CDM lamps are also available in versions for a closed fixture. Remember, these are NOT to be used in open reflectors:

The CDM Elite 315 Agro is the most suitable for plant production, as it produces the most photons in the PAR spectrum. However, if you are looking for the best colour reproduction and most sun-like spectrum, the 942 would be the best choice.

efficiency (10% less light – 1.7 µmol s-1 per Watt!) and a lower light maintenance. You can recognise it by the arc tube shape, which is less round than the original. Most of the private label CDM lamps all come from that same factory.

Limitations • These lamps require a specific low-frequency ballast.

Most are around 200 Hz and provide the lamp with a square wave output. The ballasts have a warm restart protection, which automatically times out re-ignition for about 10 minutes.

• The lamp holders only receive the /O type CDM lamps.

• The output power of 315W. There are higher wattage CDM lamps available, but these have not been optimised for plant growth, are not as efficient, nor do they provide the same light maintenance. Perfect for general lighting, not for plant lighting. The 315W being the only real available option means that in order to get the same output as a 1000W DE HPS running at 100%, you need 3.5 – 4 CDM fixtures. This translates into a higher overall investment and more maintenance. The CDM lamps are slightly less efficient than DE HPS (1.9 µmol s-1 per Watt versus 2.1 µmol s-1 per Watt) and have a lower light maintenance (3-4% less light maintenance per year), so the average light output is actually a little bit lower.

The spectrum of the CDM, however, is superior over the HPS lamp: It contains much more blue than the HPS lamp.

By no means does the CDM 315 Agro mimic the sun, but you can expect a healthier plant. Most advantages will be seen in the morphogenesis of the plant and the production of terpenes and essential oils. To really make a difference in that latter department though you will need to start adding UV light in safe dosages. It will not, however, result in an extra-spectacular yield.

So Where Would I Use the CDM 315 Lamp?

A big advantage of a lower wattage is that you can come closer to the crop. Using more, low wattage lights instead of one large fixture, will give you a better light uniformity and horizontal penetration of the crop. If you have a small room, and the money to invest in more fixtures, a few CDM 315W lamps really do an outstanding job. In vegetative rooms where you need less intensity, and more blue light is an advantage, CDMs can also be a solution. Do remember that in a large room, the initial investment can be quite high.

China! China!

Of course, there are other CMH lamps out there, many coming from China. There is one manufacturer who makes a decent lamp with a good spectrum, but with a lower

To counter the lower wattage limitation, there are even double ended lamps which contain 2 or 3 CMH arc tubes in series. This is not a good plan, as it can lead to ignition failures and premature failures of one of the arc tubes. Also, remember that MH and CMH lamps need to have a double jacket to be suitable for use in an open reflector, and use a LOW-frequency ballast with a time-out for re-igniting warm lamps. They are NOT suitable for a retrofit to a highfrequency HPS lamp!

So, there you have it: A primer in CDM and the application of it. A great lamp, with some limitations. Is it a full HPS replacement? For small grows it can be, due to the high investment costs compared to HPS. Does it replace full spectrum plasma lights? Though it is more efficient, the spectrum is still a bit too peaky to mimic sunlight, and the lamp lacks UVA and UVB. CDM is an expensive lamp to replace every year, but for a small cash crop that should not be a limitation.

Retrofit Warning There are many (Chinese) double ended MH lamps sold on the market today for use in open, double ended fixtures. A REALLY bad plan, for many reasons: • These lamps do not have a /O rating (with one exception, which uses an extra glass cylinder around the lamp).

• Many discharge very high UV levels, making it dangerous to work under without proper protection. One manufacturer proudly announced that they emitted “the good UV – UVC.” • Most double ended fixtures have specifically been developed to drive HPS lamps, which do NOT need a warm re-start protection.

Running MH lamps on these ballasts is dangerous, as re-starting a warm MH lamp can lead to an explosive failure of the lamp. We have been able to replicate this in our labs. Do NOT try this at home, boys and girls!

• You will lose the warranty on your ballast if it has been specifically designed for HPS lamps. 3

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PLANT A-HEAD

These head planters are totally cool - indoors or out.

They come in a range of colors and sizes from extra small to huge. Some have the option of glow in the dark lighting too. A Teresa Sapey design exclusively from Vancome made from recyclable polyethylene.

The Adan Nano Pot is not illuminated, but very affordable, and perfect for small plants. You might find other uses for it too, like a vase or sculpture with stash space. Dimensions: 13cm x 17cm x 18cm (5.12” x 6.68” x 7.09”). Shipping worldwide from bit.ly/ head-global, or in the UK from bit.ly/head-uk.

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SMART COMPOSTING

No need to invest a lot of money or build a bin. The Compost Sak from Smart Pot is easy to use, and perfect for small budgets. Place it in the sun where it will get rain. Water during dry spells. Holds 100 gallons of kitchen and yard waste and because of the constant air flow from all sides and the top, you’ll get faster composting action.

Produces 15 cubic feet of compost and measures 30”W x 38”H (76cm x 96cm). Available from many stores, including Amazon in the US, CA, and the UK.

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W E E D WA R R I O R

Here’s an excellent garden tool from the past brought back to life by a company in Ohio. An incredibly useful tool in the garden - anyone who’s used an old one has been hunting for one of their own for decades. The open blade makes it lightweight and gives you a fore and aft cutting action as you shuffle it along.The sharp point is great for digging out larger weeds.

Designed for many years of service with a long ash handle and hardened steel blade. Exclusively from Lehman’s Non-Electric Hardware.

Ships internationally: bit.ly/weed-hoe.

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PL ASTI C POTS I M PROV E D

Increase air flow to the roots of plants in plastic or ceramic pots with the Smart Soil Separator. It also doubles as drainage space creator for pots without bottom holes and can be used to turn any non-draining container into a wicking pot.

Designed to work in a range of pot sizes through adjustable tabs fanning the air/water filter center.They also make these durable plastic separators for large containers, but currently available only in North America due to the difference in pot dimensions.

Made in the USA by Nature’s Footprint.

Shipping to the UK: bit.ly/separator-uk.

US and Canada: bit.ly/separator-na.

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WICKED DIGGER

Designed to handle whatever you need to conquer today. Remove old shrubs, dig in clay, pry rocks, cut sod, plant something, divide rhubarb... Root Slayer will make many yard and garden projects easier. The latest tool from Radius Garden, this combination of shovel, root hatchet, and root saw is everyone’s new favorite shovel.Winner of the 2017 Green Thumb Award for best tool innovation.

Patented ergonomic O-grip offers 4 times more leverage. Sharpened tip cuts like butter, carbon steel shaft, heavy duty, and a lifetime guarantee. Available from Amazon in the UK, US, and CA. (Search “root slayer.” Red, round handle, top result.) 3

As I am writing this article, we have just been notified that we can not build our booth at the trade show. We worked on it more than one hour, and if it takes more than an hour to set-up, it is the union workers that have the right to completely take over and, ask you ridiculous sums of money to do what is your job. At some shows, you are not even allowed to carry in anything that is larger than a laptop bag or use a dolly to transport stuff to your booth.

Don’t get me wrong. I am a big advocate of worker’s rights, and the unions have been instrumental in getting proper labour conditions and salaries, but this is turning more into a mafia than a worker’s association.

this is turning more into a maf ia than a worker ’s as sociation

We do trade shows all over the world, and in 99% of all countries, it is not an issue to build your structure, as long as you do it safely and according to the general building codes and regulations. Not today, not in the USA. I totally understand the resentment of some people against unions, as some of these rules are absolutely ridiculous.

Six years ago, three unions fought over who had the right to build our booth. The electrical crew argued that it was a rigging job because of all the illumination and fixtures we had, the construction guys reasoned that it required building a structure, and the venue’s workers claimed the work as it was on their turf. In the end, we did most of the work ourselves because of the incompetence of the labour assigned to us.

At some of the shows, we pay more for “handling” of our goods (which means that they receive it at the dock and bring it to your booth and, if you are lucky, without a forklift damaging your crates) than shipping it across the country. It depends on the venue and the contract that the

show organisers have with the venues and the unions whether you need to use them or not. But clearly, this is completely getting out of hand.

I am a liberal. I’m all for worker’s rights. But there is something very wrong with this system. In no other country are the costs of building a booth as high it is in the USA because of these regulations. And it is not necessary, as is proven time after time in other civilised countries, where the off-loading and loading is part of the venue’s services, you do not pay anything extra for that (all included in the booth price), and you are free to build your own.

There may be strong safety regulations, which is fine with me, I’m all for that. But creating jobs that actually should not be there, and employing non-skilled workers to mess up your expensive booth is making some US shows into a living nightmare. Of course, this is not everywhere, and we have done the same shows in different states where there was not an issue at all.

Before I did trade shows in the USA, I didn’t understand the impact of this system and why there was so much opposition towards unions and their power. First-hand experience has changed this completely.

Still, I’m all for unions in general. I just hate to be ripped off. 3

​With known and suspected dangers posed by the use of pesticides, non-chemical alternatives continue to be of interest to the average grower. Most indoor growers have encountered problems with spider mites, thrips, or whiteflies, and they know these pests can seemingly spring up out of nowhere.

Fortunately, there are predatory insects that can be released to control the problem.

Predatory Mites Though “fighting fire with fire” may be cliché, it is an approach that can be taken to control an outbreak of spider mites. There are numerous species, and a positive identification will guide your selection of the predatory mite. There are generally five species available on the market that control several different species of spider mites, as well as other greenhouse pests, and each has their tolerances for temperature and humidity.

1. Amblyseius swirskii - This versatile predatory mite can be released to control whitefly, thrips, and most species of pest mites. They are most effective in temperatures between 50-85°F (10-30°C).

2. Galendromus occidentalis - This predatory mite thrives in warm temperatures and a wide range of humidity, so long as it does not drop below 30%.

It provides control for common spider mites, such as the two-spotted and Russet mites. It can tol-

erate temperatures up to 120°F (49°C) and as low as 60°F (15°C), but does best in the 80°-110°F (26-43°C) range.

3. Mesoseiulus longipes - These mites do best in temperatures of 70-100°F (21-38°C) with a relative humidity of at least 40%. They can help control several species of spider mites.

4. Neoseiulus californicus - This species is best between 55° and 105°F (13-40°C) and tolerates relative humidity as low as 40%. This is the mite to use if the Willamette is the pest species.

5. ​​Phytoseiulus persimilis - These are best to use when two-spotted mites are the target pest. They perform best in temperatures between 50° and 90°F (10-32°C) with relative humidity above 60%.

Green Lacewings

Chrysoperla (carnea and rufilabris), more commonly known as green lacewings, are generalist predators during their larval stages. They seek out the eggs of other insects and will consume any other soft-bodied pest. They can be released to control spider mites, aphids, mealybugs, leafhopper nymphs, scales, thrips, and whiteflies. These beneficial insects are also more tolerant of pesticide use than other biological controls - if pesticides are used after their intentional release.

Ladybugs ​ robably the most widely-used and best known beneficial P insect is the ladybug or lady beetle. Like the green lacewing, ladybugs are generalists, eating almost any soft-bodied insect, including spider mites, aphids, scales, mealybugs, and leafhoppers. Both the adult and its larvae will eat pest insects, consuming up to 5,000 pests during its life cycle.

Banker Plants ​ any growers, even experienced ones, can become frustrated M while trying to use beneficial insects for control of their pests.

Once pest species have taken hold, it is often too late to release them - but releasing them before there is a sufficient amount of pest species to consume means they will leave in search

of food or die of starvation, which is a waste of money. The solution is to grow or purchase so-called banker plants. ​anker plants can be any B number of plant species that are both attractive to both a desired pest species and beneficial insects. The idea is to keep your population of beneficial insects alive and reproducing year-round, so they are already on site when fast-moving pests, like spider mites and aphids, present themselves. Banker plants are often selected to attract pests that will not transfer over to the crops that you are intentionally growing, but provide food and a habitat for the beneficials that you are trying to maintain.

A Precaution… ​ eneficial insects are often just as susceptible to pesticides as B the pests to be controlled. If your particular control strategy is to use both pesticides and beneficial insects, make sure to apply the pesticide first, and allow sufficient time to pass before releasing the insects. If pesticides are to be used prior to a release of beneficials, make sure to use only those contact pesticides that do not have a residual killing effect, such as horticultural oils or insecticidal soaps. 3

1) Exeter, Devon

Grounds Have 3 Lives Many people know coffee beans have two lives: brewing and enriching the compost pile. But while trying to conquer the art of growing mushrooms in his room at university, Adam Sayner realised there’s a third life sandwiched between purposes A and B. Brewing coffee only removes 1% of the nutrients.

He pioneered mushroom farming in spent coffee grounds, creating both the indoor GroCycle Urban Mushroom Farm and home grower mushroom kits.

Since 2011, GroCycle has recycled 62,337kg of coffee grounds, shipped 29,932 home growing kits, and supplied gourmet mushrooms to local chefs. The novel reclaimed grounds and cardboard growth media Sayner developed has drawn great interest from other mushroom growers. How-to inquiries started stacking up, and cultivation education added a third avenue for the social enterprise to make an impact. To date, 862 people in 42 countries have taken their online course.

An amazing sustainable startup gone viral. Learn more: www.grocycle.com

2) Ashley Vale, Bristol

Green Mecca St Werburghs City Farm is a multi-faceted space in one of the UK’s most disadvantaged areas. They’ve been improving community and people’s lives for 30 years. A delight for locals and visitors - it’s the place to meet, get married, take a stroll, learn, get involved, and a family outing hot spot with an adventure playground and room to romp.

The charity has a 2-acre farm complete with animals, 1-acre community garden, 2.5-acre conservation site, and 13-acres of allotment gardens. Their awardwinning cafe serves meat and produce grown on site. Other attractions include fairs and summer programs, crafts, and gardening courses, volunteer projects, and more. St Werburghs also works with at risk youth in a Work2Learn placement scheme, provides employment for young adults, and strives to empower them all by building confidence and skills.

An invaluable asset where everyone is welcome and accepted.

Learn more: bit.ly/SWfarm-feature and swcityfarm.co.uk

3) Fforestfach, Swansea, Wales

Saving The Farm The only city farm in Wales has been actively involved in their community since 1998, promoting environmental awareness and personal growth through participation. Swansea Community Farm is the place for fun, building confidence, and learning skills, including gardening, healthy cookery, and where food comes from. No matter what age group you’re in, there’s always something going on at Fforestfach’s 3.5 acre volunteerrun working farm.

Thanks to Lottery funding, the farm built a cafe in 2012 that serves meats, eggs, and produce grown onsite. It provides a source of income in addition to various courses offered, like beekeeping. But times have changed, charitable grants and donations no longer cover everything. Through grants and

crowdfunding this spring, the long-standing social benefit fended off closure for another 6 months by raising £50,000 in 30 days.

Success, though one step at a time, is still success. Even social charities need strong sustainability plans today. Learn more: bit.ly/SCF-site.

4) Totnes, Devon

Food Forest Projects Turning a 2-acre field into a forest doesn’t happen overnight.

The Agroforestry Research Trust began work on the Forest Garden Project on Dartington Estate land in 1994. The 140 species of large fruit and nut bearing shrubs and trees that form the canopy have filled in well with time. Understory plantings of fruiting shrubs and perennials now thread their way through the grassy groundcover.

The Trust conducts intensive agroforestry research and education on both academic and practical levels. They offer courses and tours, sell seeds and plants, and publish a quarterly journal. Now, trust director and agroforestry pioneer Martin Crawford is ready to create a tropical food forest inside a greenhouse constructed last summer that’s heated by soil heat storage. The canopy trees; citrus, avocado, banana, papaya, and more will be planted this year.

The first sustainable indoor tropical food forest in the UK! Learn more: bit.ly/AFT-site. 3

Isn’t breathing great? Something we unconsciously do all day long so our body can perform all sorts of processes by making use of that lovely little element we know as oxygen. Controlling your breathing can be key to all manner of advantages, almost any yoga practitioner can testify to that. It can even allow your body to do some things you would usually think impossible.

Take my bro Wim Hof, for example. This guy truly shows what proper breath control can do for the body. He conquered Everest and Kilimanjaro wearing nowt but a pair of beach shorts and shoes, then ran a full marathon in a desert (50°C/122°F) with no food or water. Taking the body to the limits of its performance is second nature to this guy, and it’s all done simply by the way in which he controls his breathing.

It’s something he says anyone can do with the right knowhow, although I can think of slightly less dramatic ways of demonstrating it. Sorting out my wife’s snoring would be good enough for me.

The point is that something often taken for granted can be used to increase productivity in a living organism massively. CO2 is no different to plants in that respect. It’s that crucial little 0.030.04% of the atmosphere that can (and does) have a significant impact on a plant’s growth, but is something that more often than not is entirely neglected by the average grower. Let’s face it, some growers can’t even be arsed with proper pH, EC, temperature or humidity control, so monitoring and controlling CO2 is unlikely to even enter their thoughts. Tsk, tsk.

Why CO2 Works

The photosynthesis equation - don’t let the science scare you.

Behold! Photosynthesis in all its glory! I guess this is technically six photosynthesises. Six waters and six carbon dioxides are needed to create one bit of energy the plant can then make use of in various ways. It also makes six oxygens as a by-product. So essentially, there are three potential limiting factors involved in photosynthesis and the production of energy for growth: light, water, and CO2.

Light Light isn’t particularly a limiting factor for most modern day growers. In fact, quite the opposite. Modern lighting fixtures can provide an almost overwhelming amount of photons for a plant, often to the point of overkill. That’s a little bit beside the point here though. All you need to bear in mind is that there is (usually) not a shortage of light for photosynthesis, and if there is, buy yourself a better light. Simple.

Water Water can potentially become a limiting factor for photosynthesis. Not only because of the lazy watering habits of some growers, but also from extreme amounts of transpiration on an excessively hot day. With inadequate root pressure, and a lack of water stores, stomata will close up, and photosynthesis will stop altogether (usually in the last hour or so of the day period). With correct climate control measures though, this factor can be completely negated, leaving only the third and final option as a limitation for creating energy.

CO2 CO2 levels, in a properly vented grow room, will likely fluctuate around the background CO2 levels you would typically encounter in the outside world. Roughly around the 300-500 parts per million (PPM) level, depending on where you are in the world. Of course, that is provided you have an adequate exhaust system refreshing the air at an appropriate level for your room size.

We all are fully aware that the more available light there is, the higher the potential for photosynthesis, meaning more energy to produce more flowers and, therefore, realise a higher yield.

This is a concept most growers are fully aware of, and should need little explanation. Everyone loves banging more lights up in their room. What is commonly less understood, and often only seen as a ‘pie in the sky’ idea, is that the exact same thing can be said of CO2. When you look at the equation, it should be starkly obvious that the more available CO2 there is, the more energy that a plant can make with it. After all, life on this planet is carbon-based, plants being between 80% and 90% of it in total. Put simply... more carbon, more yield.

So, Where Are You Going With This?

The aim of the game is to extract this carbon from the air and photosynthesise sugars, a process known as assimilation (assimilating the three different elements to create energy).

Mostly though, this energy is used (dissimilated) by the plant to go about its day-to-day business. Basically, using a lot of this energy for all the things a plant needs to do, just to maintain itself: delivery of water, sugars or nutrients, to name but a few tasks.

Finally, any energy left over after all the dissimilation has taken place is put into new growth. So essentially, if you can assimilate more, then it logically follows that more energy is left over for the plant to channel into new growth and a higher yield. It shouldn’t be a surprise to you that increasing CO2 levels above the background PPM’s is one way you can achieve larger, higher quality yields.

Ok, I’m Convinced. How Do I Do This?

There are many ways to supplement your CO2 levels which can be categorised in two distinct ways. One is way more effective than the other, but both have their places.

Non-steered 1) Sing to Your Plants!

Turns out my Nan wasn’t as crazy as she appeared to be when she sang to her plants. Us humanoids exhale a vast amount of CO2 as we breathe, and your plants will make use of this! In reality though, no-one is likely to actually do this for twelve hours a day. Unless, of course, you are as mental as my Nan was, bless her rotting cotton socks.

2) Fermentation Brewing your own booze, either using a sugar and yeast combo or a mycelial (fungal) mass will produce CO2 as a byproduct. Not in huge amounts mind, but depending on your grow room, you may well notice benefits by adopting these methods.

3) Growing At Night It is actually quite common practice for growers to run their rooms overnight, particularly in areas that offer more affordable rates of electricity during that period. Why is there more CO2 overnight though? Well, the dissimilation process produces CO2 as a by-product, and as it carries on overnight (when assimilation and photosynthesis have stopped), elevated background levels of CO2 will be seen.

4) ‘Flip-Flop’ Grow Rooms This is when you have two grow rooms side by side, both on 12 hours of light, but on opposite time frames. The extra CO2 produced during ‘lights out’ from one room supplements the other room that is in its ‘lights on’ period. The only problem with this is the average temperature and humidity of one grow room will directly affect the other, so it is harder to steer things like day and night temperature differences or humidity levels in each individual room.

Controlled With the appropriate monitoring and dosage equipment, you can make sure the CO2 levels are at exacting levels at any given time. Typically, a probe will measure the levels of CO2 in the room and relay data to a control unit that then doses according to the desired presets. Needless to say, placement of the probe is fairly crucial to ensure you are getting a good general average reading of your room. The same can be said of the dispersion of the CO2 itself - try to ensure whichever delivery system you use achieves as homogeneous a level of CO2 across your room as possible.

1) Compressed CO2 Bottles Used in conjunction with the appropriate dosing equipment, compressed CO2 is one way to supplement your room to exacting levels. The CO2 is compressed and pressurised into liquid form, expanding into gas upon dispersal.

2) CO2 Generators Propane or butane gas burners can be used, creating a decent amount of CO2 as the by-product to the flame. You also get heat and water (humidity) from it though, so extra attention and controls may be required to combat this.

It Can’t All Be Winner-Winner Chicken-Dinner There are always downsides. The first hurdle, in this case, is that to have a grow room that can precisely monitor and control CO2, you will need a considerable amount of buckshish to invest in equipment. Not only for the release system itself, but also being best practice to grow within a sealed environment - pricey air conditioning units, dehumidifiers, and other such bits and bobs are needed.

Basically, you’re gonna have to spend some duckets to pimp the bejeesus out of your room to get the most of CO2. Plus, know what to do with it all.

Not only having an impact on your wallet and time, the additional CO2, of course, influences your plants’ growth habits. Understanding that impact, and being ready to adjust for it, is crucial for things to continue going nice and smooth.

So, What Does It Do to the Plant?

For the most part, it boils down to CO2’s effect on the stomata. In the presence of elevated CO2, the plant’s initial response is actually to partially close them up. It’s a little bit like how the irises in your eyes will respond to light levels, reducing their size to almost pin-hole level when it is really bright (or sometimes just on a heavy night out, but I digress).

Closing the stomata slightly limits transpiration. Limiting transpiration reduces the plant’s cooling capacity. A reduced cooling capacity means the plant’s temperature increases.

An increased plant temperature means a higher metabolic rate. An increased metabolic rate translates into a greater potential in the photosynthetic rate. Finally, the increased photosynthetic rate means the higher CO2 levels can be used more efficiently. The balance between the increased CO2 and temperature is achieved, so the plant operates as effectively as possible. Bingo.

The problem with closing the stomata and limiting transpiration means the balance between that and the root pressure will also change - typically ending up in a situation where that balance lies heavily in the favour of root pressure. Without compensating for this impact by adjusting the environmental conditions, you will see the results in the form and structure of your plant. With all that extra water being pumped in, there is an increased stretching between nodes, larger leaves, and a higher likelihood of things like guttation or botrytis. Of course, these are undesirable and need to be overcome.

30-32°C (86-89°F) will force the plant to cool itself more, which it will do by opening its stomata back up again. Your plant is now in a position of maximum metabolism (enhanced rate of photosynthesis from the CO2 enriched environment), and the balance of root pressure and transpiration means it’s form is perfect.

In addition to an increased temperature, as your plant is now some sort of turbocharged monster, you can afford to raise other things, such as light levels and leaf area index (LAI). It will also require a compensation of your EC. Tinkering with these parameters to find the ideal balance without pushing your plant past the limit is something that will take considerable experience. The effort you invest, however, is entirely worth it, and will reward you in heaps and bounds.

The safe way for the beginner is to start increasing PPM’s after the initial stretch period of the flowering phase is finished. Raising it by 200-300 PPM to the required maximum every three to four days. Even if you haven’t compensated your environment correctly, the plants are naturally less likely to stretch out of control. If you are a growing genius, you can crank it up pretty much straight away, but you need to be all over your environmental control, right from the get go.

Crank Things Up, Baby!

This is where the supercharging part of the article title comes in. The aim of the game now is to open those stomata back up again. We want them open as wide as possible to increase transpiration, and also to make use of even more of that lovely extra CO2.

There are many ways to influence this in your climate, but usually, the easiest and most effective way is to raise the temperature. For example, if you typically run a temperature of 28°C (82°F) before supplementing CO2, raising this up to

Lots of Effort, Lots of Rewards Let’s not beat around the bush... supplementing CO2 involves time, effort, and brainpower. It increases the chance of things getting out of control, and can swiftly kick you in the nuts if you take your eye off the balls at any point. However, it can result in a vast increase in yield, which is surely the goal of any self-respecting grower. Hopefully, this collection of words has inspired and helped you to understand what is initially involved and set you on course for a fantastic adventure in the land of CO2. 3

We currently find ourselves at a unique point in the history of humanity, when more than three-quarters of all North Americans and Europeans are living in cities.

Constant urban sprawl means that the food needed to feed city dwellers has to be produced farther and farther away, hundreds or even thousands of kilometres from our cities, before it is shipped there by plane, train, or truck - generating all kinds of pollution and greenhouse gases. This lengthy shipping time forces growers to produce fruit and vegetable varieties that are firm, contain little juice, and have thick peels or skins capable of standing up to the constant handling, shocks, and temperature changes. And since it can take several days, if not weeks, for produce to reach our plates, it often has to be picked before it’s fully ripe. The end result is that all this food too often isn’t very flavourful or nutritious by the time it gets to us.

The FAO estimates that 53% (you read that right, more than half!) of all the food produced in the United States and Canada is lost or thrown out before it can be eaten, partly because of spoilage in shipping or handling. In the UK, it was found that 8 million tonnes gets wasted post-manufacture.

That makes it more essential than ever to produce healthy food, locally, right in our cities. But it takes a lot of creativity to grow edible plants in an urban setting where there’s little land available, or what land there is for sale or rent is very

expensive. So, people often end up growing fruit and vegetables on building roofs and walls. To meet this urgent need, some highly promising new technologies have appeared of late – ones like garden towers, making it possible to grow edible and fruit-bearing plants in the most confined and inhospitable spaces!

The current popularity of vertical gardening owes much to experiments conducted in the late 20th century by Brazilian landscape architect Roberto Burle Marx and French botanist Patrick Blanc. They were among the first to show that plants can be grown vertically, without any soil. Although both men focussed primarily on plant walls, they were also interested in green towers. Such structures are especially well-suited to urban agriculture, because they can be used to grow edible and fruit-bearing plants in really tight spaces. A tower barely 80 cm (32”) in diameter and 1.8 m (6’) tall can produce the same amount of food as a regular 4 or 5 m2 (43-54 ft2) plot of land.

Soil-based garden towers

Rich potting soil

Some types of garden towers use mosaiculture techniques – they’re built from light metal frames covered in a geotextile membrane. In some cases, 80% greenhouse shade cloth is used instead of geotextile. Another option is to recycle old fabric (denim is great) to cover a tower. Attach the geotextile membrane to the metal structure with metal fasteners or plastic tie wraps. Then fill the tower with potting mix, packing it down to avoid air pockets. An even simpler tower can be fashioned from a ring of wire mesh, with straw around the edges to hold in the soil.

The potting mix used for this type of garden tower must be rich and light. A blend containing equal parts compost, sphagnum moss, and perlite. Personally, I use Pro-Mix Organic Vegetable and Herb Mix – which provides good water retention and the nutrients plants need. Since some nutrients will leach out, you also need to add plenty of fertilizer to the soil to ensure that the edible plants you plan to add have all the nutrients they need to grow and thrive. Slow-release, natural, granular fertilizer that’s high

Use a drip irrigation system running inside the metal frame, about 10 cm (4”) from the edge, with the nozzles spaced no more than 30 cm (1’) apart. Since the water will seep through the soil by gravity, run the irrigation hoses from the top to about halfway down the tower, and simply hook them up to an outdoor faucet. It can also be very useful to place the system on an electronic timer.

Add your plants after first making holes in the geotextile membrane with a metal or wooden dibber, like the kind used for planting bulbs. Make the holes just slightly larger than the plant root balls, from 2 to 6 cm (1-2”) in diameter. Anything larger than 6 cm (2”), and it will be very difficult to make the holes and add the plants.

in nitrogen and potassium, of the 5-3-8 type, usually does the job for most vegetable plants grown in such towers.

You’ll need to mix in 1-2 kg (2.2-4.4 lbs) of this fertilizer per m3 (35 ft3) of potting soil.

In subsequent years, since you won’t be able to add granular fertilizer to the soil, you can use liquid fertilizer, like liquid seaweed for instance, adding it through the irrigation system with a siphon or metering pump. You can also simply spray liquid fertilizer onto the plants’ leaves. After four or five years, you will usually need to open up the textile covering the tower and remove the potting soil.

You may find that you’re able to remove all the old roots, mix the soil with compost and reuse it, although after all that time the soil will probably have lost its structure and ability to retain water and nutrients, and will need to be completely replaced. You can dispose of the old soil by composting it or spreading it on your garden beds.

Green fence The system described above can also be used as a fence or freestanding wall. For this type, you need a wooden or metal structure, wire mesh, and geotextile membrane.

Add the wire mesh, like the type used for reinforcing concrete, before the geotextile membrane to prevent it from bulging under the weight of the potting soil. Then fill the wall, about 40 cm (16”) wide, with potting soil, so that

you can add your edible plants along the sides.

Unlike a plant wall resting against the wall of a building, a freestanding wall – which looks like a wide fence – can be planted on both sides. Depending on which way the plant fence is facing, some of the plants will receive less sunlight than others, especially those on the north-facing side. As with a plant tower, you need to add a drip irrigation system to a freestanding edible plant fence.

Aeroponic garden towers Other types of garden towers are available on the market. They consist of recycled plastic tubes with openings in their sides for the plants. Each tower also has a tank at its base for holding water that is then pumped to the plants through tubing. This is an aeroponic system with nutrient-filled water being sprayed onto the plants’ roots inside the tower. Such towers are usually quite expensive, but you can make one at a fraction of the price from a wide-diameter plastic tube.

What to plant in your garden tower Unlike container gardening, not all fruit and vegetable plants can be grown in a tower. For example, indeterminate tomatoes and cucumbers aren’t suitable, because they will tend to hang and cover a large part of the tower, preventing the plants lower down from growing properly. Determinate varieties with compact, shrubby growth,

like ‘Tumbler’ or ‘Tiny Tim,’ are much better suited. You can also grow eggplants and sweet peppers that produce small fruit, such as the ‘Little Fingers’ or ‘Lunch Box’ cultivars. Surprisingly, potatoes do well in towers. It’s easy to make your own potato tower by drilling a few 5 cm (2”) holes in the sides of a garbage can.

The edible plants best-suited for towers are herbs and leafy vegetables, like swiss chard, spinach, kale, and leaf lettuce. Dwarf beans and compact snow peas, like ‘Little Snow Pea,’ produce excellent crops when grown in towers.

Strawberries are the ideal berries for growing this way.

Dwarf blueberries, like the Jelly Bean™ cultivar, and lingonberries can also be grown vertically, provided you give them acidic soil, with pH lower than 6.

Don’t forget to add a few edible flowers like nasturtiums, pinks, and pansies to your garden tower. They’ll also attract the pollinating insects needed to grow most edible plants.

To continue this extreme horticulture experience, go to albertmondor.com/en 3

Arm yourself with as much information as possible when designing your indoor grow space - it becomes much easier to know what size tent to buy or how much reflective sheeting you will need if you know the exact the dimensions of your grow room. It is also vital for planning how many lights you will need to illuminate that space efficiently. Knowing room size and the number of lights gives you confidence that you are picking the correct size fan and filter to extract stale, hot air and bring in fresh cool air.

All of this information is helpful when deciding the number of plants to grow but, more importantly, knowing these plants’ requirements allows you to prepare for success, including picking the correct pot size. A pot that’s too small for the plant will restrict root growth, and an oversized pot can lead you to spend more money on media and nutrients.

Proper planning not only increases the chance of success but keeps more money in your pocket. And knowing roughly how much nutrients the plants will require, you will be less likely to run out just as your shop closes for a long weekend.

Be sure to have it all worked out before you even step foot into a grow shop. They will be better equipped to help you choose the right equipment for your unique environment.

Bring your room dimensions and your list. If you don’t have a detailed list, you will inevitably forget something or worse, get the wrong item.

Keeping an eye on the weather forecast means you can make adjustments to the grow room environment preemptively, rather than reactively. This anticipation keeps plants in the best environment for increased growth and production rather than hindered due to adverse conditions such as high temperatures. It’s planning to be adaptable that will allow you to follow the plant’s rhythms.

“Plan for the worst and hope for the best” is a good grow room mantra. Plant deficiency, high or low temperatures, unexpected electricity surges, faulty light hangers, ballasts and bulbs, the influx of pests during the summer or the insidious effects of a disease can all be mitigated with a little foresight.

When you have a plan, you bring the future into the present, and there’s always something you can do in the present! Now, go and buy a tape measure. 3

Plants react when introduced to different levels of air pressure. For several decades, researchers have been conducting numerous trials while looking at the suitability of various crops to grow in areas all over the world. Additionally, there has been a significant amount of study done on plants throughout the history of the space program, as any long-term voyage outside of Earth’s atmosphere may have to rely on the ability to grow food in the conditions in space, both onboard vessels and potentially on the surface of other orbiting bodies.

Trial Results

those raised

Plant Reactions to Changes in

​ ost plant species trials at differing M Air Pressure in the higher elevations and air pressures have been Plant physiology and plant development ​ conducted on field crops or those air pressures differ by significant measure depending that may be potential sources of oils on the amount of air pressure, whether were less or fibres. Crops, such as cotton and resulting from the altitude acting upon able to absorb maize (corn), and less common ones, them or not. In general, the higher the nutrients such as Lesquerella, have been studied. altitude, the shorter the wavelength of In the case of Lesquerella, when grown radiation from the sun and, therefore, at elevations below 1200 ft (365 m), the crop proved to increased intensity of available light. This bodes well yield more seed and five times the biomass, as compared for photosynthesis, however, as altitude increases, the to the same species grown at higher elevations. The plants temperature often decreases about 50°F (10°C) for each themselves were also approximately twice as wide and tall 3300 ft (1000 m), which is not conducive for many species as their counterparts. of flora.

Cotton and corn grown in greenhouse settings with twice the average amount of air pressure yielded twice the dry weight, and 60% greater leaf area, as compared to those raised in “normal” environments. However, those raised in the higher air pressures were less able to absorb nutrients (nitrogen).

Water movement within plants (transpiration) expands as air pressure decreases, and as altitude increases.

If moisture is available to the plant, transpiration rates continue to rise, and a plant’s stomata remain open.

Growing Indoors at High Latitudes and Altitudes ​ rowing marketable crops at higher altitudes, and often G higher latitudes is challenging for several reasons. In general though, the indoor grower can mitigate many of these challenges. The shorter photoperiod of higher latitudes can be overcome by adding grow lighting. Supplementing CO2 in the growing area will increase yields, and the time required for ripening of indoor crops.

I​f you live at a high altitude and intend to garden, there are plants and strains that are acclimated to your unique situation. The best way to grow in these areas is to select a species that has adapted to its characteristics.

To discover plants suitable for your area, inquire at your cooperative extension office or visit local garden centers.

They should both have people on hand to help you make

an informed decision about what to grow at your altitude and latitude. There is also a plethora of recommendations out there on a variety of websites and forums. With some trial and error, you might just become the resident expert on how to grow at your altitude. 3

You need more than just water as the heat index climbs in summer. Quenching that thirst from hydration lost to perspiration could be more effectively conquered with juices. A recent study by the University of Aberdeen Medical school found that water-rich fruits and vegetables are twice as good.

The reason? The hydrating salts, minerals, and sugars they contain work much like isotonic sports drinks... but better. Natural juices also give you vitamins, fiber, and beneficial compounds.

The top three hydrating options are watermelon, cucumber, and celery. The trio contains essential rehydration salts that help move the water they contain through your system. The natural sodium, potassium, magnesium, calcium, phosphorous, iron, and zinc are similar in balance to the fluids lost by the human body via sweat. Replacing that is the key to proper hydration.

Not only does it rehydrate, watermelon also has the added benefit of boosting your body’s protection against UV rays.

Get that juicer or blender out, and create your own recipe for something truly thirst-quenching on the hot days ahead.

Source: bit.ly/hydrate-more

No matter how big an apple is, it floats. The reason is that they are 25% oxygen. Yet, air quickly turns apples brown when sliced or bitten into? Pretty puzzling.

Among the many health benefits of bananas are its natural antacid effects, and stomach and intestinal health promoting properties. High in fiber, the low-acid fruits offer a home remedy for both heartburn and indigestion. They are thought to be helpful for acid reflux relief, and may protect against ulcers.

Source: bit.ly/gastro-relief

The meat of an apple is formed of billions of individual cells - that’s where the juice is. The air that makes them buoyant is locked out of the cells until the walls soften in the overripe stage of maturity.

They’re also mealy at that point, because the juice is now dehydrating.

Ever notice that mealy apples turn brown faster? You can’t eat them fast enough!

The browning of an apple is a bruise, no matter how inflicted. Like blood rushing to where the hammer mashed your finger, the darkening is an enzymatic reaction to the flood of oxygen to an apple’s injured cells.

Source: bit.ly/apple-brown