Maximum Yield AUS Nov/Dec 2012

Australia November - December 2012

I N D O O R

G A R D E N I N G

FREE s: d n i F ear G Newm the Fro ow Gr ld Wor

& Achieving the Perfect Harvest DIY Alert: Reuse Your Media maximumyield.com

Consider the Climate Factor

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CONTENTS November/December 2012

FEATURES 24

20

20 Reuse, Reuse, Reuse Your Media

by Grubbycup

24 How to Successfully Choose Growing Media

by Guy Sela

34 30 The Symbiotic Relationship

Between CO2 and Ventilation

by Matt LeBannister

34 Treat ‘Em Bad and They’ll Taste Better: Improving Flavor

by Dr. Lynette Morgan

44 Curing the Flaw: Maintaining Consistency With a Greenhouse Ventilation System

by Dr. J. Benton Jones, Jr.

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Maximum Yield | November/December 2012

DEPARTMENTS

6

From the Editor

8

Letters to the Editor

10

Simon Says

12

MAX Facts

16

Product Spotlight

40

10 facts On…

46

Growers Know

50

Distributors

52

Did You Know?

54

Coming up Next

54

MaximumYield.com

44

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FROM THE EDITOR | lINDA jESSON

Message from the

Editor Linda Jesson

Here comes summer, and with that comes all the hot weather concerns for keeping our garden growing optimally. This issue industry experts share tips and tricks on mediums and ventilation to help you through this hot spell. These two important components of a successful grow are often overlooked, and I know that the articles in this issue will offer some great insight and advice to help your garden thrive.

Are your plants too hot or too cold? Are they getting enough CO2 or are they getting too much? Air in a growroom or greenhouse can be hot, stale and suffocating thanks to grow lights and other heat-emitting equipment. Your plants simply want to be comfortable, which is why Matt Lebannister talks you through controlling your environment to propel plant production. Dr. J. Benton Jones, Jr. also discusses some design flaws that cause—and some possible solutions to cure—the significant problem of moving air within a greenhouse.

On the topic of mediums, Guy Sela details the physical properties growers need to be concerned with when choosing between the options available and Grubbycup shares why (and how) to reuse your media.

In addition to media maintenance and ventilation advice, we have added some of the other top-ofmind growroom issues like maximising photosynthesis, controlling climate and gardening for apartment dwellers. There is a lot here for you, so enjoy this issue and be sure to drop us a line with your success stories or queries. We are here to help!

contributors Matt LeBannister developed a

Dr. J. Benton Jones Jr. has 50

Raquel Neofit is a freelance writer

for the horticulture, travel and lifestyle industries. She has a background in business and radio, and is an avid believer that hydroponics is the future.

Follow Raquel’s writing on her blog, Black Thumbs Guide to Growing Green—the misadventures of the vertical herb gardening movement— and My Food Story on Facebook.

Grubbycup has been an avid indoor gardener for over 20 years.

His articles were first published in the United Kingdom, and since then his gardening advice has been published in French, Spanish, Italian, Polish, Czechoslovakian and German.

He is also considered one of the world’s leading authorities on crochet hydroponics.

Dr. Lynette Morgan holds a B. Hort.

Guy Sela is an agronomist and a

green thumb as a child, having been born into a family of experienced gardeners. During his career, he has managed a hydroponic retail store and represented leading companies at the Indoor Gardening Expos. Matt has been writing articles for Maximum Yield since 2007. His articles are published around the world.

Tech. degree and a PhD in hydroponic greenhouse production from Massey University, New Zealand. Lynette is a partner with SUNTEC International Hydroponic Consultants and has authored five hydroponic technical books. Visit suntec.co.nz for more information.

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Maximum Yield | November/December 2012

years of experience growing plants hydroponically. He is an Emeritus Professor at the University of Georgia, Athens and has authored eight books and written articles for magazines that deal with hydroponic issues.

He currently has his own consulting company, Grosystems, Inc. Dr. Jones currently lives in Anderson, SC, USA.

chemical engineer for his innovative software company, Smart Fertilizer (smart-fertilizer.com), which provides fertilizer management solutions.

Applying his background in water treatment, he has lead a variety of projects on reverse osmosis, water disinfection and water purification, and providing high-quality water for irrigation.

Become a Maximum Yield contributor and have your articles read by 250,000 readers throughout USA, Canada, UK, Australia and New Zealand. Maximum Yield is the largest free-to-consumer indoor gardening magazine in the world. Every issue is available on maximumyield.com, which has thousands of unique visitors monthly.

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LETTERS TO THE EDITOR VOLUME 10 – NUMBER 4 November/December 2012

Commenting on Compost

First of all, I’d like to start by saying I love the magazine. The Greenhouse & Water issue (Maximum Yield July/August 2012) had a lot of pertinent subjects.

Can you publish an article on essential microbes? [It’s] a subject I just heard of from a knowledgeable person working at one of the indoor gardening stores in your directory. When I asked for Alaskan humus, wanting compost that was supercharged with microbes and many beneficial stains of fungus like mycorrhizae, he told me to look into essential microbes, populations of microorganisms and beneficial bacteria you can harvest, colonise and breed yourself.

Thanks for increasing awareness in diverse issues pertaining to this beautiful art and science of growing plants in progressive ways.

Sincerely, Oskar Newsman, aka G.I. Grow Stay tuned for upcoming issues of Maximum Yield for articles that highlight your specific requests and answer your questions.

Falling for You

Is there any way to get a subscription of Maximum Yield (MY) in the mail? I fell for MY and I always get excited for the next issue. I know there is the digital copy and it’s good for going green; and I know I can view the magazine on my smartphone, but it’s just not the same. I like having the actual magazine in my hand that I can carry with me everywhere.

I love the magazine and articles. [As a new cultivator], I have learned much from the MY mag.

Thank you for your time and producing such a great magazine for free!

Phillip Good Of course! A subscription form is available for download from maximumyield.com/ subscriptions

We’ve Got You Covered

Great magazine this month. I hate to judge a book by its cover, but I knew from the cover I would enjoy it, and sure enough I am. Keep up the good work helping people get their maximum yield.

Davy Stanford

Nuts About Nutes

Loving the new issue this month!

The focus on the nutrients was especially awesome.

North Country Hydroponics

From Stressed Out to Easy Street Maximum Yield reserves the right to edit for brevity.

We want to hear from you!

Maximum Yield Publications Inc. Snail-mail: 2339 Delinea Place, Nanaimo, BC V9T 5L9 E-mail: editor@maximumyield.com Twitter: twitter.com/max_yield Facebook: www.facebook.com/MaximumYield

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via Facebook

Maximum Yield | November/December 2012

Because of your magazine I was able to pinpoint the problem of my garden. It was in bad shape for a couple weeks. Turns out heat stress caused by 37°C weather and no airflow, plus a small case of chlorosis is bad combo.

I’m a first-time gardener; after about three years, [I became] seriously fed up with in-ground garden maintenance, weeding and such. It was too big of an area to maintain by myself, so I started a grow box. It’s much easier, I must say, as far as maintenance goes. I just want to say thank you for the education.

Juan Martinez

PRINTED IN AUSTRALIA Maximum Yield is published bi-monthly by Maximum Yield Publications Inc. 2339A Delinea Place, Nanaimo, BC V9T 5L9 Phone: 250.729.2677; Fax 250.729.2687 No part of this magazine may be reproduced without permission from the publisher.

If undeliverable please return to the address above.

The views expressed by columnists are a personal opinion and do not necessarily reflect those of Maximum Yield or the Editor.

Publication Agreement Number 40739092 PRESIDENT/PUBLISHER - Jim Jesson GENERAL MANAGER - Don Moores BUSINESS MANAGER - Linda Jesson editorial editor@maximumyield.com Editor Linda Jesson Assistant Editor Jessica Skelton ADVERTISING SALES 250.729.2677 Ilona Hawser - ilona@maximumyield.com Ashley Heppell - ashley@maximumyield.com Emily Rodgers - emily@maximumyield.com Kelsey Hepples - kelsey@maximumyield.com PRODUCTION & DESIGN ads@ads.maximumyield.com Art Director Alice Joe Graphic Designers Liz Johnston Jennifer Everts Dionne Hurd ACCOUNTING Tracy Greeno - tracy@maximumyield.com Tara Campbell - tara@maximumyield.com

AUSTRALIAN DISTRIBUTION Dome Garden Supply Holland Forge House N’ Garden Hydroponic Generations Plant Symbionts UK DISTRIBUTION Growth Technology Future Harvest Development Europe Nutriculture UK Direct Garden Supplies Dutch Pro Maxigro Ltd. Hydrogarden CANADIAN DISTRIBUTION Brite-Lite Group Biofloral Eddis Wholesale Greenstar Plant Products Inc. Hydrotek MegaWatt Quality Wholesale USA DISTRIBUTION Aurora Innovations BWGS General Hydroponics Humboldt Wholesale Hydrofarm Hydro International National Garden Wholesale / Sunlight Supply R&M Supply Tradewinds

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SIMON SAYS

Hello Simon, Is it beneficial in any way to monitor one’s runoff water after drenching one’s soil with nutrients?

Some say you can see the chemistry between your plant and its nutrients more efficiently, but I personally see it as totally unnecessary. I have never seen the need for it because I always seem to get drastically false readings on my pH pen when testing the runoff. My plants always look fine if I just stick to controlling the pH level of my nutes before applying them to the soil.

Thanks, Kyle S.

Waste-water testing can yield important information for a grower. In a recirculating system, the runoff needs to be monitored to ensure an adequate level of nutrition and that the nutrients in suspension are available to the plant (based on pH levels).

It sounds like you are in a soil/soilless-based system, so I will tailor the answer to that style of gardening. I will also guess that you are growing in a peat-based medium. The first issue of growing in peat is the pH of the material. With a pH range usually hovering between 4.0 and 5.0, peat requires a calcium supplement to boost the pH to a useful range.

In most cases, the manufacturer will add lime as a buffer. This is the first reason for you to check your runoff. The buffering effect of the lime only works for a certain amount of time, especially with frequent watering.

After this point, the pH of your medium will drift lower and lower.

Runoff pH can also be affected by the plants themselves. Plants have an internal pH regulating system and they can also affect the localised pH around the rhizosphere (and thus the runoff) by releasing exudates to suit their needs. The last major reason

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Maximum Yield | November/December 2012

that your runoff pH can fluctuate is the presence of biology in your medium. In a bacterial-based system, the pH will generally drift up. In a fungal-based system, the pH will drift down.

Your inaccurate readings probably relate to one of these issues. It is possible for the pH of the runoff to be much different than the solution you feed to your plants. (Just remember to keep your testing equipment clean and calibrated to be on the safe side.)

Assessing the runoff concentration can help you stop overfertilisation. (Peat has a cation exchange rate, meaning it can retain certain types of nutrients. Once these exchange sites are saturated, the nutrients in solution can reach levels harmful to your plants.) It will also show you if high levels of soluble nutrient are draining through your medium and away from plant roots.

The problem in assessing the salt level is that you do not know the specific elements that are causing the reading. For the average home grower, the tests available cost more than they are worth. In your case, seeing healthy-looking plants is the best observation possible.

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MAX FACTS

hydroponic news, tips and trivia

It’s All in the Know Scientists believe they’ve pinpointed the last crucial piece of the puzzle of how plants “know” when to flower. According to research, determining the proper time to flower–important if a plant is to reproduce successfully–involves a sequence of molecular events, a plant’s circadian clock and sunlight.

“If we can regulate the timing of flowering, we might be able to increase crop yield by accelerating or delaying this. Knowing the mechanism gives us the tools to manipulate this,” said Takato Imaizumi, an assistant biology professor.

(Source: sciencedaily.com)

MAXFACTS

hydroponic news, tips and trivia Zooming in on Insect Pests When an insect pierces the surface of a plant to feed, much of the action takes place in the plant’s interior. A device called the Electrical Penetration Graph (EPG) is a critical tool for peering into the process. Now a new type of EPG developed by scientists is providing the clearest view yet of the wars waged between insects and the plants they attack.

(Source: ars.usda.gov)

Research Seeks to Protect Western Australian Tomato Industry New research aimed at protecting interstate market access for Western Australian tomatoes is underway. Department of Agriculture and Food development officer Rohan Prince said the plan was to develop a new, safe postharvest treatment to protect fruit from the Mediterranean fruit fly.

Three new gases that do not damage or affect the shelf-life of the tomatoes—ethyl formate, propylene oxide and ethanedinitrile—will be tested to develop a process that satisfies interstate quarantine authorities.

(Source: freshplaza.com)

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Maximum Yield | November/December 2012

Crop Improvements Need new Tech to Happen Researchers at Purdue University and the USDA Agricultural Research Service argue that scientists could take greater strides toward crop improvement if there were wider adoption of advanced techniques.

Today’s technology could allow scientists to match physiological and genetic characteristics of plants with the soil characteristics that promote or inhibit their growth. Making those connections could reduce the time necessary to improve plants that are coping with changing environmental and climatic conditions.

(Source: sciencedaily.com)

High-performance Organic Corn In conditions of drought, organic corn yields were 31% higher than nonorganic. According to Rodale Institute’s long-running side-by-side trials of organic and non-organic farming, it comes down to the differences in soil managed through chemical fertilisers versus those managed organically. Organic farmers use compost and manure to replenish nitrogen, as well as grow legume cover crops that trap nitrogen from the air and deliver it to the roots of plants. Then there’s the benefit of crop residues left in the field. As a result of these differences, organically managed soils trap more carbon in the soil—and all of that carbon allows these soils to hold in water and nutrients better in drought conditions.

(Source: treehugger.com)

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Maximum Yield | November/December 2012

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MAX FACTS

hydroponic news, tips and trivia

First Ever Record of Insect Pollination from 100 Million Years Ago Amber from Cretaceous deposits in northern Spain has revealed the first record of insect pollination. Scientists have discovered in two pieces of amber several specimens of tiny insects (namely, Thysanopterans, or thrips) covered with pollen grains.

“This is the oldest direct evidence for pollination, and the only one from the age of the dinosaurs. The co-evolution of flowering plants and insects, thanks to pollination, is a great evolutionary success story...

Thrips might indeed turn out to be one of the first pollinator groups in geological history, long before evolution turned some of them into flower pollinators,” concludes Carmen Soriano, who led the investigation of the amber pieces with X-ray tomography.

(Source: sciencedaily.com)

Researchers Use Oxygenated Phosphine Fumigation to Control Insect Pests A fumigant called phosphine is more effective at controlling insects when it’s combined with oxygen, according to findings by a scientist in the United States Department of Agriculture. The oxygen-phosphine combination could be an environmentally friendly alternative to methyl bromide for combating pests on harvested fruits and vegetables.

(Source: ars.usda.gov)

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Maximum Yield | November/December 2012

New Shallot Varieties An Australian company is now offering several new shallot seed options to growers.

The new varieties will offer competition to the current limited range.

(Source: freshplaza.com)

Glass Ideal Alternative to Perlite, Parboiled Rice Hulls A recent study compared perlite and parboiled rice hulls—two common components used to increase air-filled pore space (AFP) in substrates— to a new aggregate produced from finely-ground waste glass. The experiments showed that new aggregate resulted in a higher AFP and a higher water-holding capacity than equivalent perlite-containing substrates. As such, it was concluded that the new aggregate could be used as an alternative to adjust the physical properties of peat-based substrates.

(Source: sciencedaily.com)

Lawton Rose in Chisholm TAFE’s controlled environment horticulture training facility, overlooking their luscious hydroponic crop.

Online Hydroponic Education Chisholm Institute of TAFE is offering hydroponic training via an online platform called the eGlasshouse program.

Students are able to study nationally accredited courses from Certificate III to Diploma. These courses are part of what Chisholm instructor Tony Bundock calls a blended learning program. Students complete their theoretical training online before undertaking practical training for the hands-on components at the Cranbourne glasshouse training facility.

For more details on these courses, contact Tony at tony.bundock@chisholm.edu.au

Australian Survey Shows Popularity of Local Produce A recent survey commissioned by the Australian Made Campaign has shown that Australians prefer to purchase local produce, with nine in 10 people stating they buy Australian-made or -grown food over cheaper imports.

Australian Made campaign chief Ian Harrison said that Australians continued to purchase local produce due to confidence in safety and quality.

(Source: ausfoodnews.com.au)

Maximum Yield | November/December 2012

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PRODUCT SPOTLIGHT

YOUR GUIDE TO THIS ISSUE’S

HOTTEST ITEMS Ask for them at your local indoor gardening store.

Introducing Can Fan RK

Can Fan RK plastic tube fan is a backward centrifugal extractor that uses a resistant, maintenance-free plastic housing. The extractor is speed controllable using voltage or frequency, and is equipped with a thermal switch that turns off the motor if it reaches a dangerous working temperature. The Swiss-made motor, together with the propeller design, enables this type of fan to deliver strong air flow while making less noise. Can Fan RK comes with a two-year warranty when used within proper conditions. For efficient performance with the best possible results, we strongly recommend the use of Can Fan RK together with Can Filters. Ask for the Can Fan RK at your favourite indoor gardening shop.

Introducing Xtreme Boost

NF Regulator The Nutrifield Plant Growth Regulator comes with two parts. Part A stops upward height growth by blocking the action of gibberellic acid. This helps to create a more uniform canopy height and thickness, resulting in even light penetration. The slowing of top growth increases lateral branching, allowing the plant to maximise its flowering sites. Part B aids in the developmental cycle, leading to increased flowering and harvest weight. It also improves density, leads to uniform flower formation and improves fruit setting. Focusing the plant on flowering shortens the harvest cycle.

Part B also prevents premature fruit drop and increases plants’ ability to resist collapse, drought, cold and alkaline-media conditions. For more information, visit your favourite indoor gardening shop.

Xtreme Boost consists of 23 different proteins, natural flowering hormones and vitamins, and organic macro- and micronutrients from seaweed kelp and vegetable matter. This was specifically designed for the flowering and ripening of your plants. Xtreme Boost enhances metabolic growth, stimulates bud development, promotes enzyme production, improves resistant to disease, encourages fruit swelling and increases essential oils. For more information, visit your local indoor gardening retailer.

Cyco ProKits now Available in Mini Versions The Cyco Mini ProKit is the perfect introduction to the Cyco line. The Bloom and Growth Mini ProKits include all the additives necessary to complement the basic Cyco Bloom A and B or Cyco Growth A and B nutrients. Both Mini ProKits contain 1 L each of Cyco Silica, Cyco Zyme, Cyco B1 Boost and Cyco Uptake. In addition, the Bloom Mini ProKit features 1 L of Cyco Swell and Cyco Potash Plus, while the Growth Mini ProKit includes 1 L of Cyco Dr. Repair and 95 g of Cyco XL. The application chart employs a colour-coded feeding schedule, making this one of the most user-friendly systems available. Visit your nearest indoor gardening shop for more information.

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Maximum Yield | November/December 2012

Growstone Super Soil Aerator: A Horticultural, Scientific and Environmental Triple Win Growstones Super Soil Aerator is a breakthrough horticultural product made from 100% recycled glass. A high-performance alternative to perlite, they are 100% American-made and chemical-free. Growstones Super Soil Aerator holds the perfect balance between air and water content at field capacity. They’re highly porous, helping oxygen flow to roots and delivering 70% more aeration than perlite. Ideal for growing a wide variety of plants, this lightweight soil aerator leads to consistent plant development and yields. It’s also guaranteed not to float to the top of mixes or wash away when irrigated, and they keep consistent physical integrity over time after multiple usages.

For more information, visit your favourite indoor gardening shop.

Root Pouch can Handle Anything Root Pouch’s smaller-sized containers are now available with handles.

The black and grey 3.79-, 7.58- and 11.37-L containers come with the choice of handles or no handles. Root Pouch offers the option to have handles in the 3.79- through 379-L pots. The handles make the containers easier to move and carry.

Our fabric containers allow water and air to flow through its walls, nourishing the root structure of the plant. It also does not allow the plants’ roots to circle. For more information, visit your local indoor gardening shop.

Maximum Yield | November/December 2012

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PRODUCT SPOTLIGHT

Root Pouch Introduces Boxer Brown, the Most Durable Pot Available Root Pouch’s most rugged line is designed to be used season after season. Our Boxer Brown pot is perfect for the great outdoors and hydroponic growing systems, and is available with and without handles. The brown fabric is made of recycled water bottles. All seams and stitching are reinforced and done with an industrial-strength stitch to deliver a stronger, sturdier bag. In tests, the bag has been reused and washed 20 times. When a kangaroo fights with another kangaroo, it is often considered boxing, which is where the name Boxer Brown originated. For more information, visit your local indoor gardening shop.

Smart Grow Pro Gardener Nutrifield’s Smart Grow Pro Gardener system allows for various growing styles—satellite, flood-and-drain, deep-water-culture and top-feed. Adjustable to meet your plants’ needs, the system can be rotated to three different heights to increase storage of water, and improve air flow and drainage for maximum growth. The distance to the light source can also be changed as your plants grow. The unique grate allows rapid drainage, holds all types of media and is excellent for deep-water-culture because the roots can grow through. The pots’ flat surfaces promote excellent connection to plumbing fittings, ensuring no leaks and easy maintenance.

Sturdy, ribbed construction protects against breakage and a squat design allows for optimal root growth. For more information, visit your favourite indoor gardening shop.

Lucius Maximus Digital Ballast Lucius Digital Ballasts are the most technologically advanced ballasts in the market.

They are energy-saving ballasts with a durable design with no fans or moving parts attached to them. They also work on both HPS and MH lamps. These ballasts help lamps provide higher lumen output and they require a low start-up current. Lucius Ballasts also operate silently and require very little maintenance. Finally, these ballasts come with a dimming control and are available in 400, 600 and 1,000 W. For more information, visit your favourite indoor gardening shop.

Feel the Rush With Cyco Cyco Suga Rush contains potassium, which is essential for the translocation of sugars, allowing your plants to build additional carbohydrate reserves. Suga Rush consists of several different sources of simple and complex carbohydrates, improving aroma and flavour in food crops. This product provides ample phosphorus and potassium to boost photosynthesis, strengthens root systems and help plants grow rapidly and withstand stress. Visit your nearest indoor gardening shop for more information.

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Maximum Yield | November/December 2012

Introducing Iso Max Iso Max is a totally unique diagonal tube fan designed to be efficient, powerful and silent. Iso Max, like Max Fan, uses the stator-rotor system that enables it to be efficient, air performance-wise and power consumption-wise. Iso Max is integrated in a silencer. The housing of the fan is made completely of metal with special foam used for noise reduction. Its lightweight, strong air performance and quiet, making Iso Max the most advanced choice for a ventilation application. Iso Max is speed controllable using voltage or frequency, and is equipped with a thermal switch that turns off the motor if it reaches dangerous temperatures. Iso Max comes with mounting brackets and a two-year warranty when used within proper conditions. For efficient performance with the best possible results, we strongly recommend the use of Iso Max together with Can Filters. Ask for the Iso Max at your local indoor gardening shop.

Root Pouch Chameleon Line, now With Handles By popular demand, Root Pouch now offers handles on their 18.95- to 246.35-L Chameleon container line. Root Pouch’s chameleon line uses the same award-winning technology and industrial-strength, reinforced stitching as their standard handles that have received such great reception. The camouflage style, perfected by military forces around the world, allows the containers to blend into their surrounding environments.

Sometimes you just want to blend in. For more information, visit your favourite indoor gardening shop.

Maximum Yield | November/December 2012

19

Reuse, Reuse,

Reuse Your

Media

by Grubbycup During harvest time, there is first the joy of collecting the fruits of your labour, and then starts the somewhat less entertaining chore of

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Maximum Yield | November/December 2012

cleaning up and getting ready for the next season. Here’s a way to cut down on the amount of stuff you have to throw away while you’re at it...

The amount of refuse that your garden creates can be reduced if the growing media is reused. In fact, in the case of organics, reusing the growing media is my preferred method. Also, nutrients that remain in the plant waste material can be then recovered and reused.

Reusing garden media is not always the best choice, however, as certain growing mediums—such as rockwool—are not very suitable for repeated use. Any plant material or media that has been exposed to a pathogen should also be removed from the system in order to prevent the disease from spreading. For example, a single plant infected with the dreaded tomato mosaic virus can infect growing media and future crops grown in it for years; hence why infected plant material and media should be isolated and destroyed. Another concern to be taken into consideration is that several chemical sources of nutrients can leave heavy metal and salts behind after macronutrients have been used, and this can result in slowly rising amounts of both toxins over a period of years. This problem is faced by soil fields where long-term heavy use of chemical fertilisers has damaged the natural microflora-based nutrition cycles.

Still, even with the above considerations in mind, there are many times when reusing media and leftover plant material not only makes sense from an economic standpoint, but from a nutritional one as well. During growth, plants distribute the nutrients they absorb throughout the plant, not just in the harvested portions. As such,

Any plant material or media that has been exposed to a pathogen should also be removed from the system in order to prevent the disease from spreading.

Maximum Yield | November/December 2012

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Reuse, reuse, reuse your media

throwing away growing media before it has completed processing the available nutrients is like collecting the dinner plates halfway through the meal.

there is a quantity of valuable nutrients still locked in the plant material and roots, and the media attached to the roots. These nutrients can be reclaimed from the leftover plant material through composting.

A hot compost pile will produce compost in a matter of weeks, but even a cold compost pile will often be ready for use in a matter of months—just in time the following planting season. (Note that while any moist plant material will eventually decompose, making an actual compost pile helps to speed the process and to contain the mess.) The resulting compost is a valuable garden resource that, in soil gardens, can be used as an improving amendment to add to the growing media or as the basis for new potting mix. Hydroponic gardeners can use the compost for teas.

Also, keep in mind that many organic nutrient sources can take months or even years to become processed by microfauna into available nutrients. As such, throwing away growing media before it has completed processing the available nutrients is like collecting the dinner plates halfway through the meal—you’re throwing away nutrients that have been absorbed by the media. Reusing media is important to maximising nutrient extraction and although reused hydroponic media might not appear as pretty as new media, it might in fact be a superior growing medium that improves with use. Remember, however, to rinse well any media that might contain high levels of salt or other chemical residue before reusing. In my own garden, the media I use is a combination of mostly perlite, with a smattering of clay balls and grow stones that I repeatedly reuse (I add fresh new media as needed).

For composting, start with the plant material and root balls. Plant material grown with either organic or chemical fertilisers can be composted to reclaim nutrients. Indeed, chemically fertilised plants tend to be larger than their organically grown counterparts and therefore can offer additional value when composting techniques are used. During fall harvest, there is not only a plethora of garden waste to deal with, but often

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Maximum Yield | November/December 2012

leaves from trees. Combining even amounts of “greens” (high-nitrogen carbon waste like leafy plant leaves) with “browns” (low-nitrogen carbon waste like tree leaves) in a pile will allow this garden trash to become compost.

Potting soil is also reusable and compostable, and while durable hydroponic media does not compost in the traditional way, it can be run through the process alongside organic material to form a pre-amended compost material.

adding additional nutrients and other enhancements to the composed media can improve the quality of the media and reduce the amount of additional nutrients that will have to be added during the growing season.

Even some questionable media can be salvaged though a process known as soil solarisation—gnats in particular can be successfully treated with this method.

Place the media in closed black plastic garbage bag and cover with a clear plastic tarp tent. Allow to sit in the summer sun for several days. Internal temperatures can be checked with a compost thermometer. Peak temperatures of over 48.89ºC for a couple of weeks is hot enough to kill many weed seeds and garden pests.

Higher temperatures (71.11ºC is often easily obtained in sunny areas) will semi-sterilise the media within a few

hours, killing most friendly and pathogenic microflora.

Media semi-sterilised in this method should have beneficial bacteria and fungi reintroduced after treatment, or mixed with inoculated soil before use.

Indeed, adding additional nutrients and other enhancements to the composed media can improve the quality of the media and reduce the amount of additional nutrients that will have to be added during the growing season. Meals, manures, worm castings, kelp and granite dust are commonly added to replace lost nutrients. Peat moss, coir and garden soil are sometimes also added to improve structure.

While we are considering reuse of resources, recirculating systems waste less fertiliser than drain-to-waste systems. If a drain-to-waste system is implemented, it should drain not to waste, but to an additional vegetable or flower garden plot. This would both maximise the use of purchased nutrients and minimise nutrient pollution leaving the garden.

Gardens cannot be closed systems. Harvested material is removed from the garden; however, that does not mean the amount of additional resources required to enter the garden and the amount of non-harvest resources leaving the garden cannot be minimised to reduce both gardening expenses and carbon impact.

In natural systems, both macronutrients and micronutrients grow plants, which then fall and decompose to become available for new plants to grow. Natural growth does not replace its growing media each year; it reconditions and improves the existing media over a period of years. Gardeners often think of gardens as an event, with a beginning in the spring, a summer in the middle and an end in the fall; in natural settings, gardens are a self-sustaining cycle. Proper additive application should seek to improve the media over time, not damage it. Nutrients and additives must be added to the garden to replace that which is removed as harvests, but there is little reason to have to start from scratch each season.

Nutrients and additives must be added to the garden to replace that which is removed as harvests, but there is little reason to have to start from scratch each season.

Maximum Yield  | November/December 2012

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by Guy Sela

Choosingtherightgrowingmediumforyour crop is crucial to a great yield. Here, Guy Selarunsthroughallyourchoicesofmedia accordingtotheirphysicalproperties…

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Maximum Yield | November/December 2012

Container production has been expanding in recent years.

Choosing the optimal medium requires special consideration because it is much more than just an anchor for the plant— it can be crucial to a successful crop. Physical and chemical properties of growing media differ from those of soil, and container production requires more attentive management.

There are many advantages to using growing media: • High yields can be achieved in a limited area • Better control over irrigation and fertilisation • Easier disinfection • Recycling of drainage water is possible • Growing media can be used as an alternative to an inadequate soil However, there are also some disadvantages: • Nutrient-holding capacity is low • Buffer capacity is low and, therefore, changes are rapid In this report, we focus only on the physical properties.

The chemical properties will be discussed at a later date.

“

Physicalandchemicalproperties ofgrowingmediadifferfromthoseof soil,andcontainerproductionrequires more attentive management.

”

Physical properties of the growing media A balance between air content and available water is one of the most important requirements of good media.

Ideal growing media provide plants with adequate water supply and, at the same time, contain enough air to allow gas exchange and oxygen supply in the root system. Aeration is critical for optimum plant development, as a lack of adequate aeration results in poor plant growth, susceptibility to diseases and nutrient deficiencies.

Good growing media are also characterised by high hydraulic conductivity—that is, the ability to transmit water.

Another important property is the medium’s weight. It should be light enough for easy and less expensive transport and handling, but it should also be heavy enough to provide physical support to the plant.

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Maximum Yield | November/December 2012

25

hOW TO SUCCESSFULLY CHOOSE GROWING MEDIA

Growing medium and production system compatibility It might be surprising, but in order to choose the best medium, the first thing you should do is consider the production system’s specifications. These factors include the type of irrigation technique (dripper’s density and discharge), containers size and containers shape. These specifications and the growing medium must be compatible in order to obtain effective and uniform distribution of the irrigation water.

Porosity and water-holding capacity Each growing medium has a characteristic particle-size distribution. The spaces (pores) between the solid particles can be filled with either air or water, and are referred to as “total porosity.”

Each medium contain pores of various sizes. Smaller pores can retain water with more force than larger ones, and a large pore cannot hold water against gravity. As such, the higher the pore is positioned in the container, the smaller it has to be in order to retain water against gravity. So, pores at the top of the container that are too large to hold water against gravity are empty; therefore, the top of the container will always be dryer than the bottom. At the bottom of the container, all pores—including the largest—are filled with water, making the bottom layer saturated. Let’s visualise...

Pores in a growing medium can be viewed as a series of capillaries. In our model (Figure 1), the width of the column represents pore size and the capillaries have been “ironed out” so they are straight and can be easily compared to each other.

It is easy to understand why the bottom of the medium is always saturated, while the top of the medium contains less water and more air. There are forces that make the water climb in the capillaries against gravity—however, these will not be discussed here. We will only mention that they are called cohesion (which is the affinity between water and particles surface) and adhesion (which is the affinity between water and itself).

Figure 1

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Maximum Yield | November/December 2012

“

Irrigationfrequencyandamount ofwaterappliedwitheachwatering aredeterminedbytheavailablewater content of the medium and by the container shape and size.

”

Water retention curves Labs can accurately measure the water percentage by volume (v/v in %) at given heights of the medium, after saturation and drainage. The height is measured in centimetres and the data can be graphically presented as a water retention curve. Some labs refer to the height as “tension in centimetres.”

Figure 2

Let’s take a look at an example of water retention curves for two different growing media (see Figure 2). The two media have completely different behaviours. Medium B drains more easily and holds less water than medium A at any given height (tension). For example, at 20 cm medium A holds 60% water, while medium B holds only 23%. This is because medium A contains higher percentage of smaller pores. Therefore, a grower who decides to grow in medium B under the same conditions (irrigation technique, container size and shape, and cultivar) has to give more frequent irrigations. On the other hand, if the grower decides to grow in medium A, his main concern would probably be lack of aeration.

Other information that we can obtain from water retention curves is the amount of water available to the plant roots.

We know that tiny pores can retain water extremely well; however, they might also hold water so forcefully that the plant cannot absorb it.

In growing media, water at tensions of 50 to 100 cm is generally considered unavailable to the plant because it is retained in very small pores. In addition, a high content of unavailable water can set the stage for fungal problems and other diseases present in high humidity conditions.

Figure 3

Containers size and shape It was mentioned above that the size and shape of the containers in which the medium is placed determine the amount of water that the media can hold. Take a look at the containers in Figure 3: All containers are of the same volume and are filled with the same medium. The blue area represents water. Since it is the same medium, the water reaches the same height in each of the containers.

Moreover, according to the water retention curve of this medium, the same water content in percent is measured at this height.

However, due to the different shapes, the actual amount of water is different in each container.

This results in a different water/air ratio in each container and in different irrigation management. Irrigation frequency and amount of water applied with each watering are determined by the available water content of the medium and by the container shape and size. For example, one irrigation cycle a day is not enough if the daily water consumption of the plant is higher than the amount of available water in the medium.

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Hydraulic conductivity As the name suggests, hydraulic conductivity is the rate at which a medium transmits water. Hydraulic conductivity of media is not routinely measured in lab tests. Nevertheless, it is extremely important to understand its significance. Hydraulic conductivity is, in fact, the limiting factor of water uptake by plants in container media (rather than the water quantity in the medium).

When transpiration rate exceeds the hydraulic conductivity of the medium, the plant cannot efficiently use the water contained in the medium and could wilt. In materials used for container media, the hydraulic conductivity decreases exponentially as the medium dries. This is because continuity of water is disrupted after the larger pores empty.

Maximum Yield  | November/December 2012

27

The

Symbiotic Relationship Between

CO2 Ventilation and

by Matt LeBannister

Gardening indoors allows gardeners to control every aspect of the environment in order to propel the production of their plants beyond the norm. However, since everything in the growroom is interconnected, it can spell disaster if one aspect gets out of whack‌ 30

Maximum Yield |  November/December 2012

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The Symbiotic Relationship between CO2 and Ventilation

Like the human body, an indoor garden is a chain of networks. If one element fails or is not working properly, then the whole chain becomes weakened and the system can collapse. For example, you can have many high-quality HID light bulbs running in a room, but it will make no difference if the nutrient levels are low. The same applies to CO2-enrichment systems—if you are not ventilating the room or keeping the temperature and CO2 at a plantfriendly level, you might actually be doing your plants more harm than good.

There are a number of reasons we need to ventilate our growrooms, including excess heat and humidity.”

What can CO2 do for you?

The air around us contains roughly 200 to 300 ppm (or, 0.02 to 0.03%) CO2. Plants do well in this range, but you can supercharge your garden by enriching the atmosphere in your growroom to 1,200 to 1,500 ppm (or, 0.12 to 0.15%). When every aspect of the garden system is aligned, this CO2 enrichment can double, even triple, yields.

CO2 enrichment also allows stems and branches to grow faster, often causing tremendous growth during the vegetative stage. This can take weeks off the amount of time you need to grow your plants before they are large enough to move to the flowering stage. You can also get more crop rotations in each year, and you save time and money.

Another benefit of enriching your growing atmosphere with CO2 is that plants in this environment can handle growing at higher temperatures. In fact, they prefer it. The ideal temperature for plants in a CO2-enriched environment is roughly 29.44ºC. With the temperature in the room higher, metabolic rates within the plant will accelerate and growth will increase. This also means that you can run ventilation fans less. In summer months, you won’t need to run your air conditioning as high or as frequently. (Keep in mind that fluorescent light bulbs should not be used if you’re enriching the atmosphere of your growroom; plants grown in this environment require intense light.)

Generating CO2

There are many ways of generating CO2. Fermentation and decomposition, like the processes used to make wine or compost, are two examples. However, one issue with these methods is that it’s impossible to control that amount of CO2 being made—it can vary depending on certain factors, such

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Maximum Yield | November/December 2012

as room temperature. Also, there is the potential for odours to be produced by the decomposing organics, which would attract pests.

Using dry ice is another way to enrich your growroom’s atmosphere. Dry ice is frozen CO2 that turns to gas when it comes into contact with the atmosphere, without ever becoming a liquid. Unfortunately, it is difficult to store enough dry ice to replenish larger growrooms. Dry ice is only practical in the smallest growrooms, and even then it can be expensive.

A CO2 emitter is a practical and cost-effective way of enriching a small, single-light room with CO2. This system uses tanks of compressed CO2 and pumps it through tubing throughout your room using regulators and valves. Since CO2 is heavier than air, it is most effective when the tubing is placed along the ceiling of your room above the plants. This will allow the CO2 to fall amongst the foliage where it can be used by the plants. Also, CO2 emitter tanks can be refilled at most hydroponics retailers at an affordable cost.

CO2 generator systems are the most practical for larger-scale or commercial growrooms with multiple lights. This system involves creating CO2 by burning fossil fuels, usually natural gas or liquid propane. However, CO2 generators have a pilot light burning at all times, which can be a risk. There is also heat given off as a by-product and in rooms with multiple lights, extra heat can be an issue.

Some people use butane lamps to generate CO2, or there is always the old-fashioned technique of sitting in your growroom and talking to your plants for a few hours a day.

Regulation, ventilation and circulation There are a number of reasons we need to ventilate our growrooms, including excess heat and humidity. Ventilation is also needed when CO2 levels are toxic or too low. When enriching the atmosphere of your growroom with CO2, the trick is to manage all these things while keeping the CO2 in the air long enough for it to be of some benefit to your plants. Since CO2 is heavier than air, a couple oscillating fans positioned near the CO2 release point can do a fantastic job of circulating the CO2 and keeping it off of the floor.

When every

aspect of the garden system is aligned, this CO2 enrichment has been known to double, even triple, yields.”

As mentioned above, there really is no way of regulating how much CO2 is produced when it’s generated via fermentation, decomposition or dry ice. You only have control of how much is allowed to stay in the room, and there are some high-tech devices for measuring these CO2 levels. Some you hook up to your fans so that they vent your room once CO2 levels reach a harmful point. Alternatively, you can set up your exhaust fans to a thermostat so they vent your growroom once the room reaches a set temperature too high for the plants to thrive.

If you are using a CO2 generator or CO2-emitter system, there are some great interfacing products that totally monitor and control the levels of CO2 while monitoring the humidity and room temperature. They can shut off fans when CO2 is being generated, shut off CO2 generators when they hit the ideal level and then turn on fans when the room becomes excessively humid or too hot. These products can be expensive, but you can’t really put a price tag on total control.

Garden systems are only as strong as their weakest link.

CO2-enrichment is no different. If you are not using your exhaust fans properly, providing the right nutrients or using the right lights, you will be wasting your time by enriching your growroom’s atmosphere. However, having all these factors dialed in while boosting CO2 levels can lead to tremendous growth and yields. When gardening with CO2, the sky’s the limit.

Maximum Yield | November/December 2012

33

&

Treat‘Em Bad

They‘ll Taste Better

I m p rov i n g F l avo u r

by Dr. Lynette Morgan Dr. Morgan shares some secrets for amping up the flavours in your hydroponic crops.

When it comes to good food, we are all looking for taste, aroma and texture. Sometimes these all come together to create a sensory delight, but when it comes to fruit, vegetables and herbs, appearances can certainly be deceiving. Those huge, red succulent strawberries or juicy fresh tomatoes at the grocery store might look fantastic on the outside, but biting into them can be an unpredictable experience— sometimes great, sometimes thoroughly disappointing.

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Maximum Yield | November/December 2012

Fortunately, flavour in fruits and vegetables is something that can be manipulated to various degrees by growers—we have far greater control over growth factors in hydroponics than we do with outdoor crops—so there’s no reason for our homegrown flavours to be anything but fantastic.

What is flavour?

Our perception of flavour is actually the result of many senses acting on a huge range of aromatics and compounds within the food we eat. In tomatoes alone, we have identified over 400 volatile aromatic compounds that contribute to overall flavour experience—and there are potentially many more to be discovered. While the taste buds on our tongues can detect the basic compounds we perceive as sweet, sour, salty or bitter, they cannot distinguish between small differences. Our main taste tool is actually our nose, which has receptors that bind to compounds and can detect volatiles in parts per trillion. The combination of the tastes we detect with our tongues and the more sophisticated feedback we receive from the back of the nose gives us our overall sense of flavour.

Do we all taste flavour the same?

While we all have certain preferences, everybody’s perception of taste is different. A tomato or strawberry that one person considers particularly good might not even register as being tasty by someone else. There are many reasons for this. First, there are slight genetic differences in the way all people perceive flavour. There is even a small population of super tasters, who have a very high degree of flavour perception. Second, factors like cultural differences, age, health, gender and the memory of how something is expected to taste can play a role in flavour perception.

For the ordinary hydroponic gardener, however, the main objective is just pleasing ourselves and those we are growing for, which makes flavour assessment a little easier and a lot of fun.

The explosive pungency in hydroponic wasabi originates from isothiocyanate compounds.

Maximum Yield | November/December 2012

35

Treat ‘em bad & they’ll taste better

Why don’t fruits and vegetables taste as good now as they did in my childhood?

This is one of the most commonly asked questions regarding modern day fruits and vegetables. One reason could be that our sense of taste declines as we age, so it’s our taste perception that has changed rather than the quality of the produce itself. Also, many people only recall really great taste experiences, so it can be hard for everyday food to live up to these golden memories. Another reason might indeed be horticultural. Modern cultivars are bred for yield, without a lot of regard for flavour. Many crops are grown through the winter in heated greenhouses under low light levels, so out-of-season produce will probably never live up to that childhood memory of backyard, summer-grown flavour.

“In tomatoes alone, we have identified over 400 volatile aromatic compounds that contribute to overall flavour experience—and there are potentially many more to be discovered.”

What makes a highly flavourful hydroponic fruit or vegetable different from a watery, insipid, tasteless one?

This depends largely on the fruit, vegetable or herb being grown. In tomatoes and strawberries, for example, one of the major problems is a lack of sweetness. Sweetness is measured in brix, and most people can actually taste a difference of just one degree brix. A great-tasting beefsteak tomato has a brix of at least seven, while poor-tasting fruit often have brix levels below five. (Note that hand-held brix meters are not expensive and can be used by hydroponic gardeners who are keen to assess their own fruit.) The problem in capsicum and chillies is lack of capsaicin, the compound that produces their characteristic heat. For aromatic herbs like basil, marjoram, oregano, rosemary, thyme, mint and sage, the issue is low levels of the essential oils that give off characteristic aromas and flavours.

How do I improve the flavour of my hydroponic produce?

Flavour improvement relies on some basic principles of plant physiology. First, restricting water uptake tends to concentrate compounds within the plant’s tissue, and many

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Maximum Yield | November/December 2012

Strawberries might look fantastic, but flavour can be unpredictable.

of these compounds are related to flavour and aroma. Applying slight moisture stress—increasing the EC to create a higher osmotic potential in the root zone—is a proven way to increase dry matter and flavour in many crops. Other stress factors can also concentrate volatile compounds. For example, herbs like basil, oregano, sage and rosemary can all have their flavour and aromas increased by applying high light, dry conditions, warm temperatures or high rates of air flow.

Do the genetics of my plants matter?

The genetic makeup of hydroponic plants has a significant affect on their final flavour profile. Cultivars need to be chosen carefully and—in most cases—need to be tested, tasted and evaluated by individual growers. After all, it’s a waste of energy boosting flavours if you’re using cultivars that have poor flavour genetics in the first place.

What makes hydroponics such a great tool for growing flavourful produce?

Hydroponic growing—in particular, protected cultivation— provides a number of tools for the manipulation of flavour.

First, indoor gardeners can provide just the correct levels of light year-round, or even extend the amount of daylight to give plants that extra boost. Second, other conditions like temperature can be highly controlled to give optimum levels for photosynthesis and sugar production. Finally, indoor growers have a high degree of control over the root zone, which means elements like potassium—which is vital for the flavour quality of many crops—can be boosted at just the right stage to ensure the fruit is of the highest possible quality.

What are some specific examples of flavour improvement methods in hydroponic crops?

For hydroponic tomatoes, the flavour profile and the sugar, acid and sodium content of fruit grown at an EC of 8.0 mScm-1 was far greater than in fruit grown at an EC of 3.0.

However, increasing the EC to improve flavour via a higher percentage of dry matter in the fruit tends to give smaller fruit and lower yields. With hydroponic chilli crops EC levels as high as 8.0 mScm-1 have been applied to boost pungency with good results, although different chilli cultivars will respond differently to increases in EC. When using a higher EC to increase the pungency of chillies, it’s best to do so by increasing only the macronutrients in solution (nitrogen, potassium, phosphorus, sulphur and calcium) while maintaining the trace elements at normal EC strength levels. For crops such as onions, garlic, shallots and chives, the strong flavour and aroma we prize are derived from the presence of organosulphur compounds and have been boosted by using higher levels of nitrogen and sulphur in the nutrient solution. Boosting levels of sulphur has also been shown to increase flavours in brassica crops (such as watercress, arugula and kale) and condiment herbs (such as wasabi and horseradish).

When it comes to flavour improvement, indoor hydroponic gardeners have all the tools required to create unique and

“When using a higher EC to increase the pungency of chillies, it’s best to do so by increasing only the macronutrients in solution (nitrogen, potassium, phosphorus, sulphur and calcium) while maintaining the trace elements at normal EC strength levels.” unforgettable taste sensations. While many new growers try to provide a luxurious, highly protected and stress-free environment for their plants, this can actually be detrimental to the flavour level of food crops. Slight to moderate stress applied to plants at the right time, combined with the right genetics, will concentrate the wide range of compounds and volatiles that make the great, distinctive flavour profiles of tomatoes, aromatic herbs, strawberries and chillies. For the savvy indoor gardener, there are infinite possibilities for flavour manipulation.

Maximum Yield | November/December 2012

37

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Maximum Yield |  November/December 2012

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MaximumMaximum Yield | November/December Yield | July/August 2012

39

article title 10 facts On…Hydroponic Media

by Philip mcintosh

1. Some sources claim that the hanging gardens of Babylon was the first place that plants were grown without the use of traditional soil-based methods.

2. Nobody knows for sure how the earliest soilless hydroponics systems worked, but the first hydroponics medium was almost certainly sand (with the possible inclusion of small-sized gravel).

3. There are now at least a dozen different kinds of soilless media applied in hydroponics.

4. Inertness (non-reactivity and having no nutrient value) is usually a desirable feature of hydroponic media. Thus, most media are made from highly stable inorganic materials.

5. One exception to this inorganic “rule” is coco fibre (or, coir), which is an organic medium derived from coconuts. Wood chips are another organic medium.

6. Bricks can be recycled into hydroponic substrate material when broken up into small pieces. However, depending on where they come from, they could contain contaminants that are detrimental to plant growth.

7. A recent arrival on the recycled media scene is expanded glass. Glass is harvested from refuse collection sites and processed into a light, porous medium similar in appearance to lava rock.

8. Spun mineral fibre (commonly known as stone wool or rockwool) was a successful insulation material for many decades before being adapted for agricultural use.

9. Stonewool was first invented on the 1800s, but it wasn’t adapted for use in agriculture until just after 1970.

10. A root support medium isn’t actually required for hydroponics. Floating bed systems and aeroponics don’t use any media at all. MY 40

Maximum Yield | November/October 2012

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Maximum Yield | September/October 2012

43

CURING THE FLAW:

Maintaining

Consistency

With A

Greenhouse

Ventilation System

by Dr. J. Benton Jones, Jr.

Effectively moving air within a greenhouse can be a challenge. Here, Dr. J. Benton Jones, Jr. discusses some design flaws that cause, and some possible solutions to cure, this significant problem...

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Maximum Yield |  November/December 2012

Anyone who has grown plants in a greenhouse is well aware of the challenges associated with how air is moved into and within the greenhouse structure. Most greenhouses are designed for a specific use so that the spacing and placement of exhaust fans and cooling pads, as well as interior mixing fans, are placed to make atmospheric control within the greenhouse as effective as possible. Unfortunately, even with the best of designs, growers might constantly struggle to establish and keep the interior of the greenhouse conforming to the requirements of the plants being grown.

With most current greenhouse designs, it is not an easy task to maintain certain parameters within the interior of the greenhouse—as well as the plant canopy—when growing tomatoes. In some greenhouses, I have seen large fans mounted in the greenhouse gable area to push air toward the plants with the hope that there is sufficient force to penetrate and mix the air within the canopy. In most commonly designed greenhouses, a cooling pad is mounted at one end of the greenhouse and an exhaust fan at the opposite end, usually 1.2 to 1.8 m off the greenhouse floor. Air is pulled through the cooling pad by the operating exhaust fans, and the cooled air is pulled solely through the top half of the tomato plants, leaving much of the air within the rest of the canopy undisturbed. However, my best tomato yields were obtained in a polyethylene-covered, 9-m-wide greenhouse fitted with a cross-flow ventilation system of the exhaust fans and cooling pads mounted at floor level. This way, the air flow was being directed through the plant canopy at the base of the plants.

Having moving air within the plant canopy has several significant advantages: it has a cooling effect, it keeps the plant foliage dry and the carbon dioxide concentration within the canopy air at the ambient level and it stimulates the evaporation of transpiring water from leaf surfaces.

Maintaining upward movement of water in the transpiration stream within the plant reduces the potential for nutrient element deficiencies—for example, such water movement within the plant can reduce the potential for the occurrence of blossom-end rot in setting and developing fruit.

Keep in mind, however, that ventilation—important as it is—has its flaws. Drawing air into the greenhouse invites the potential for insect invasion; therefore, it is required that

“My best tomato yields were obtained in a polyethylene-covered, 9-m-wide greenhouse fitted with a cross-flow ventilation system with the exhaust fans and cooling pads mounted at floor level.”

all openings be properly screened. However, depending on the mesh size of the screen, air flow can be restricted. Also, ventilating the greenhouse will remove any extra carbon dioxide that has been generated to enhance photosynthesis—this is a significant, expensive loss that can reduce the effectiveness of the added carbon dioxide on plant growth. Most greenhouses in use today have these design faults. In order to correct some of these inadequacies, some growers place plastic pipes or tubes at the base of each tomato plant row. This solves the canopy air mixing problem, but other insufficiencies remain. For example, the air being drawn into the greenhouse might not be sufficient to obtain the desired temperature, relative humidity or carbon dioxide content of the interior air.

The ideal ventilation system is to condition air in its own facility before introducing it into the greenhouse through floor vents. The return air is then taken from the greenhouse gable area to be processed through the air-handling facility before introducing it once again to the greenhouse.

With such a recirculating system, the air properties can be more easily maintained at the desired temperature, relative humidity and carbon dioxide content. The only required opening into the greenhouse would be a double-door entrance for workers; therefore, there are no other openings that can provide the entrance of pests and unconditioned air into the greenhouse.

I visited an experimentally designed greenhouse where air was being conditioned in a separate facility and then introduced into the greenhouse through holed tubes running along the base of the tomato rows. The return air was drawn from the greenhouse gable and taken back into the air-handling facility for reconditioning. The initial report on the yield of tomato fruit produced was a 15% increase as compared to that being obtained in an adjoining greenhouse using the traditional ventilation system of cooling pads and exhaust fans. Based on this experience, as well as other observations I have made growing greenhouse tomatoes and advising growers, I would design a greenhouse with this type of air circulating system.

So, for growing tomatoes—and possibly for other crop plants—let’s do away with the current greenhouse designs that adversely effect the fruit yield potential of a tomato crop. I wonder who the first greenhouse manufacturer to step forward with such a design will be.

Maximum Yield | November/December 2012

45

GROWERS KNOW

Pioneering Hydroponics

by Raquel Neofit

When Chris Burges first took over his family’s market garden farm, he had a dream to grow hydroponic tomatoes. But he was met with discouragement and dire warnings of failure when he asked the Australian Department of Agriculture for advice. This response just made Chris all the more determined to succeed…

The past The 25-acre property in Heatherton, Victoria, was originally home to field-grown crops. That is, until a young and intuitive Chris sat flipping through horticulture magazines one day and stumbled across some perfect hydroponic tomatoes. Having recently taken over the farm from his father, Chris set out to investigate the world of hydroponics.

“When I called the Department of Agriculture in the Netherlands, they told me they had a representative coming to Australia if I would like to meet with him,” Chris says. “He gave me a lot of help to start with.”

This was a time when hydroponics was relatively unheard of in Victoria; the few growers that tried hydroponics before Chris had gone broke in the process. “There were many issues in the beginning,” Chris says. “For example, bacterial canker is a common problem tomato growers in Australia face, but in Europe, they’d never heard of it.” Chris puts a lot of it down to Australia’s extreme weather conditions. “Tomatoes don’t like hot weather,” Chris adds.

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Maximum Yield | November/December 2012

The present Today, Chris has 12,000 sq m under heavy-duty plastic and about 15 acres of field-grown Asian leafy greens.

Everything on-site is automated and his equipment is still purchased and delivered directly from Holland. An onsite 12-m container is home to a massive gas boiler that heats water and mixes nutrients for his greenhouse crops.

“We have to pay carbon tax now because a by-product of burning gas to heat water is carbon dioxide, but we’re not actually polluting the atmosphere,” he says. “See, as the carbon dioxide goes up the flume, we pump it into the greenhouse because plants love CO2.” Unfortunately for Chris, the Australian government doesn’t see it that way and enforces Australia’s new carbon tax payments.

Chris sticks to his old-school method of a run-to-waste system that he’s very happy with. They have, however, changed their media in favour of coco peat. “With coco peat, we split the bag, dump it in the paddock and it’s good for the soil,” Chris says.

Water samples

Water samples are taken and shipped off to the Netherlands fortnightly for testing, as is current data on crop size, growth cycles and how many trusses are flowering. The Dutch scientists reply with a new nutrient recipe based on this information and test results.

The recipe is then altered, and the weather and greenhouse conditions are checked to determine how often the crops need to be dosed.

In mild climates, dosing occurs around five times a day; however, once summer kicks in, it could be up around 40. “We have one person employed in summer who continually roams around managing the automation,” Chris says. “They check the plants, the temperature, see which direction the wind is blowing

are taken and shipped off to the Netherlands fortnightly for testing, as is current data on crop size, growth cycles and how many trusses are flowering.”

from and how much wind is entering the greenhouse. If the wind is too hot, we close the greenhouse up because we don’t want all the hot air coming in.”

The future Chris believes the future looks good for the industry because food is going to become an issue. “What’s happening is the big companies are driving the efficiencies.”

Maximum Yield | November/December 2012

47

You Tell Us

Maximum Yield: Tell us a bit about your company.

How did it start? Who are the people behind it?

Andrew Ungerleider: In response to the destructive pumice strip mining I saw taking place in northern New Mexico, my wife Gay Dillingham and I co-founded Growstone.

Perlite and pumice are volcanic rocks used as ingredients in concrete, as a mild abrasive in cosmetics and cleansers, and to abrade blue jeans. Perlite is also used in soils. Working with a ceramicist, I found an alternative [made of] recycled glass. It was a cost-effective and superior alternative that was completely earth-friendly‌We like to say that instead of mining the Earth, we mine the landfill. And the result is Growstones! They are breakthrough high-productivity soil aerators and a hydroponic growing medium. They look like porous little sponges and hold a perfect balance of air and water, which helps nutrients and oxygen release in proper ratios for ideal results.

Maximum Yield recently sat down with Andrew Ungerleider of Growstone, LLC, to discuss what makes Growstones different from other growing medium.

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Maximum Yield |  November/December 2012

MY: How did you come up with the idea for Growstones?

AU: The idea behind Growstones was to create cellular glass, which mimics volcanic silicates like pumice and perlite. The idea of foam glass has been around for a long time; in Europe, companies actually use foam glass in road construction. What I figured out was a way to take the glass and engineer it to hold the perfect balance of air and water for growing.

MY: What are Growstones made of and how are they made?

AU: They are made from 100%-recycled glass. We utilise our patented technology to recreate a volcanic reaction in a controlled environment.

The first step in our manufacturing process is crushing the glass bottles into small pieces. Then that glass is milled into a fine powder and a natural foaming agent

is added. That material is fired in a large kiln and baked.

The blend rises as it bakes and bubbles of gas are released, creating a network of pore cells in the material that form a rigid and highly porous foam with the desired physical properties. When the material comes out of the kiln on the conveyor belt, it cools down. As soon as it reaches room temperature, the product cracks into smaller chunks. These chunks are then crushed into the desired sizes.

Since our production facility is right in the landfill, no long distance transport of raw materials is necessary. This saves thousands of gallons of fuel and significantly reduces our carbon footprint. Also, the manufacturing does not use water at any stage. In the end, the results are high-performance, chemical-free, recycled and non-toxic soil amendments and hydroponic substrates.

MY: What makes Growstones different from other grow mediums? What are the benefits to using your product?

AU: Unlike expanded clay, perlite, vermiculite and pumice, Growstones are made from mining the local landfill versus strip-mining our precious mountaintops. Since we engineer the stones, we are able to create superior attributes—such as perfect balance between aeration and water absorption.

Also, our product is ultra-lightweight, dust free and does not breakdown. It even adds much needed silica back to the earth. Finally, the irregular shape of our chemical-free, nontoxic product prevents rolling.

MY: What are all the ways one can use Growstones?

AU: For aeration and oxygenation of root systems • In dry climates, to save water (it has highly efficient absorption characteristics) • As a top dressing to prevent fungus gnats • Great for lining pots and containers (it is ultra lightweight and has optimum water retention) MY: What impacts do your products have on the environment?

AU: We believe we are a restorative technology. We are diverting glass headed for land-

fills, recycling and creating green jobs, all while providing a superior-engineered product without the harmful effects of strip-mining minerals.

It doesn’t get more sustainable than that.

MY: What made you decide to expand into the Australian market?

AU: We love Australia! Growers in Australia have a long and rich tradition of indoor growing, hydroponic growing and, most importantly, a love of products that do not damage the Earth. Expanding into Australia has long been our dream, and we were approached by a key Australian distributor to bring our revolutionary product to Australia.

MY: Will your products work differently in different climates?

AU: The Growstone Soil Aerator product provides a perfect balance of air and water holding capabilities, so in wet climates, they act as a great drainage medium that miraculously prevents overwatering, and in dry climates, their ability to efficiently hold water and provide aeration promotes a healthy root mass. Growstones are used successfully worldwide in all sorts of different climates and growing conditions.

MY: Is there anything happening in the R&D stage that you’re at liberty to tell us about?

AU: We are currently working on a perfectly balanced and sized aerator/hydrator called Soil Mate Plus. This product will help everyday gardeners significantly improve their soil the easy way. Soil Mate Plus enhances aeration, improves drainage, provides optimum water retention, reduces soil compaction and prevents overwatering.

Maximum Yield | November/December 2012

49

MAXIMUM YIELD distributors AUSTRALIA ACT South Pacific Hydroponics

#2 - 84 - 86 Wollongong St., Fyshwick ACT 2609 (02) 6239 2598

South Pacific Hydroponics

70 Oatley Court, Belconnen ACT 2617 (02) 6251 0600

NEW SOUTH WALES ABC Aquaculture

54 Wahroonga Road, Kanwal NSW 2259 (61) 2 4393 3131 ASE Hydroponics

Factory 10/45 Leighton Pl., Hornsby NSW 2077 (02) 9477 3710 Ballina Hydro

3 Ray O’Niell Crescent, Ballina NSW 2478 (02) 6686 7321 Brunswick Hydro & Aquarium Supplies

19 Booyun Street, Brunswick Heads NSW 2483 (02) 6685 1552 Criscete Hydroponics and Organics

Unit 2/15 Kam Close, Morisset, NSW 2264 (02) 4973 5779

Dr. Van Der Bloom’s Hydroponics Supplies

5/5 Forge Drive, Coff’s Harbour, NSW 2450 (02) 6651 9992 Dubbo Hydro & Tobacconist 42c Victoria Street, Dubbo West NSW 2830

(02) 6885 1616 Ezi Grow Hydro 177 Mt Druit Road, Mt Druitt NSW 2770 (02) 9832 1610 Ezi Grow Hydro

1B/340 Windsor Street, Richmond NSW 2753 (02) 4588 5826 Ezi Grow Hydro

56 Fish Parade, Bathurst NSW 2795 (02) 9832 1610 Ezi Grow Hydro - Head Office

18 Part Street, Eglinton NSW 2795 (02) 6337 1485

Favgro Hydroponics Growers

107 Glenella Road, Batehaven NSW 2536 (02) 4472 7165 Felanza - Hydroponics

140 Princess Highway, Arncliffe, NSW 2205 (02) 9556 1494

General Hydroponics

7/14 Sunnyholt Rd., Blacktown NSW 9676 (02) 9676 8682 Grow Australia

Hobby Grow

6/46 Through Street, South Grafton NSW 2460 (04) 2283 8069 Home Harvest

6/376 Newsbridge Road, Moorebank NSW 2170 (02) 9824 3400

Nutriflo Hydroponic Systems

Hyalite Villawood

2/21 Birmingham Avenue, Villawood NSW 2163 (02) 9723 7199 Hydro Masta

100 Station Road, Seven Hills, Sydney NSW 2147 (02) 8812 2845 Hydro Masta Pty Ltd

76 Beecroft Road, Epping NSW 2121 (02) 9869 3011 Hydro Net

2/14 Aific Street, Long Jetty NSW 2261 (02) 4334 6955 Hydro Place

1/68 Nelson Street, Wallsend NSW 2287 (02) 4965 6595 Hydro Shop and Reptile Supplies

2/390 The Esplanade, Warners Bay NSW 2282 (02) 4958 1489 Hydro Shop Pty Ltd

Unit 1/5-7 Channel Road, Mayfield West NSW 2304 (02) 4960 0707 Hydro Supplies

57 Flinders Street, Darlinghurst NSW 2010 (02) 9326 0307 Hydro Wise

68 Bridge Road, Nowra NSW 2541 (02) 4423 3224

19/5 Daintree Place, Gosford West NSW 2250 (02) 4323 1599 Parkview Plants

Indoor Sun Shop

Quik Grow

510a Great Western Hwy., Pendle Hill NSW 2145 (02) 9636 7023 Quick Grow

823 King Georges Road, S. Hurstville NSW 2221 (02) 9546 8642 Quik Grow Pty Ltd

490 Parramatta Road, Petersham NSW 2049 (02) 9568 2900 Simple Grow

Hassall Street & Windem, Wetherill Pk NSW 2164 (02) 9604 0469 Tweed Coast Hydroponics

2/58 Machinery Dr., Tweeds Head South NSW 2486 (07) 5524 8588 Uncle Wal’s Gardenland

31 Crescent Avenue, Taree NSW 2430 (02) 6550 0221

Home Grown Aquaponics

PO Box 274, Mascot NSW 1400 1 800 661 475

Wollongong Hydroponic Center

318 Crown Street, Wollongong NSW 2500 (02) 4225 8773

745 Victoria Road, Top Ryde NSW 2112 (02) 9808 6511

NORTHERN TERRITORY

Indoor Sun Shop

17 Rundle Street, Katherine NT 0850 (08) 8972 1730

Unit 2/109 Junction Road, Moorebank NSW 2170 (02) 9822 4700 International Fans

PO Box 120, St. Mary’s NSW 2760 (02) 9833 7500 Kyper’s Tools and Hydroponics

Grow Your Own

Lismore Hydro

Unit 6/34 Alliance Ave, Morisset NSW 2264 (02) 4973 5179

1/106 Canway Street, Lismore NSW 2480 (02) 6621 3311

Happy Grow Hydro

Lismore Hydroponics

rear of 28 Casino St., South Lismore, NSW 2480 (02) 6621 3311

Unit 1/4 Windmill Street, Southport QLD 4215 (07) 5591 6501 Eye Lighting Australia Pty Ltd

PO Box 306, Carole Park QLD 4300 (07) 3335 3556

Katherine Hydroponics Centre

QUEENSLAND A Happy Medium Hydroponics

Unit2/10 Central Court, Browns Plains QLD 4118 (07) 3809 3322 Allgrow Hydro

13 - 58 Bullock Head St., Sumner Park QLD 4074 (07) 3376 7222 Aquatic Oasis

Unit 2/33 Smith Street, Capalaba QLD 4157 (07) 3245 7777 Billabong Hydroponics

Lot 1, Billabong Court, Childers QLD 4660 (07) 4126 3551

Maximum Yield | November/December 2012

Walsh’s Seeds Garden Centre

881 Ruthven Street, Toowoomba QLD 4350 (07) 4636 1077 SOUTH AUSTRALIA ------------------------------------------

Advanced Garden Supplies

2/80 Beerburrum Road, Caboolture QLD 4510 (07) 5428 1133 22 Mining Street, Bundamba QLD 4304 (07) 3816 3206 2 Sonia Crt., Raceview QLD 4305 (07) 3294 3253 Hyalite Varsity

5/11 John Duncan Crt., Varsity Lakes QLD 4227 (07) 5593 7385 Hydroponic Roots & Shoots

Lot 3 Herberton Road, Atherton QLD 4883 (07) 4091 3217

Hydroponics & Garden Supplies

Advanced Garden Supplies

3/8 Bredbo St Lonsdale S.A. 5160 (04) 1325 8818 ------------------------------------------

Amazon Aquariums & Gardening

Unit 5, 16 Research Road, Pooraka SA 5095 (08) 8359 1800 Ascot Park

753 Marion Road, Ascot Park SA 5043 (08) 8357 4700 Barry’s Hardware

Saints & Main North Rd., Salisbury Plains SA 5109 (08) 8281 4066 Bolzon Home & Garden

93 Cook St., Portsmith QLD 4870 (07) 4035 5422

103 Tolley Road, St Agnes SA 5097 (08) 8265 0665

Hydroponics Today

Chocablock Discount Variety Store

PO Box 785, Stanthorpe QLD 4380 (07) 4683 3133 Indoor Solutions

Unit 2 / 79 Oxford Tce., Taringa QLD 4068 J&K Hydroponics

10 Wacol Station Road, Wacol, Brisbane QLD, 4076 (07) 3271 6210 KY Garden

3/31 Argyle PDE, Darra Brisbane QLD 4076 (07) 3375 9098

15-17/1220 Grand Junction, Hope Valley SA 5090 (08) 8396 3133 Complete Hydroponics

1581 Main North Road Salisbury East SA 5109 (08) 8258 4022 Country Hydro

434 Saddleback Road, Whyalla SA 5600 (08) 8645 3105

Nerang Hydroponic Centre

D & W Dependable Hardware

North Queensland Hydro Supplies

Festive Hydro

27 Lawrence Drive, Nerang QLD 4211 (07) 5527 4155

45B Kettering Road, Elizabeth South SA 5112 (08) 8287 6399

Shop 2B/20-22 Fleming St., Townsville QLD 4810 (07) 4728 3957

2 Kreig Street, Evanston Park SA 5116 (08) 8523 5100

Northern Hydroponics

Fulham Gardener Nursery

383 Mulgrave Road, Cairns QLD 4870 (07) 4054 5884

Pioneer Hydroponics

194 Doyles Road, Pleystowe QLD 4741 (07) 4959 2016 SA Hydroponics

Shed 3, 1191 Anzac Avenue, Kallangar QLD 4503 (07) 3285 1355 Simply Hydroponics Gold Coast

42 Lawrence Drive, Nerang QLD 4211 (07) 5596 2250

Sunstate Hydroponics

1137 Ipswitch Road, Moorooka QLD 4105 (07) 3848 5288

Sunstate Hydroponics

67 Aerodrome Road, Maroochydore QLD 4558 (07) 5479 1011 The Hydroponic Warehouse

Shop 3/73 PIckering Street, Enoggera QLD 4051 (07) 3354 1588 Tumbling Waters Hydroponics

2 Clarkes Track, Malanda QLD 4885 (07) 4096 6443

Harvest Time Hydroponics

Shop 3/146-148, Findon Road, Findon SA 5023 (08) 8244 0222 Hindmarsh Hydroponics

39a Manton Street, Hindmarsh SA 5095 (08) 8346 9461 Highland Hydro

14/1042 Grand Junction Road, Holden Hill SA 5088 (08) 8395 4455 Hong Kong Hydro

Green Power Hydroponics

H2 Gro Pty Ltd

20 Uralla Road, Pt Macquarie NSW 2444 (02) 6581 1272

Westside Lighting & Electrical (Ezi Range)

252 Oxford Street, Bondi Junction NSW 2022 (02) 9369 3928

E.T. Grow Home

Port Pumps and Irrigation

Hydroponics Grow All Year

Hygrow Horticulture (Greenlite)

5/404 Deception Bay Road, Deception Bay QLD 4508 (07) 3204 8324

Grow Hydro

13/8a-8b Hartley Drive, Thornton NSW 2322 (02) 4028 6388

14 Fitzmaurice Street, Wagga Wagga NSW 2650 (02) 6921 5911

D-Bay Hydroponics Shop

250 Princess Highway, Nowra South NSW 2541 (02) 4423 0599

B/385 The Entrance Road, Long Jetty NSW 2261 (02) 4333 5700

Stuart & Tincogan Sts, Mullumbimby NSW 2482 (02) 6684 4928

50

14-16 Nance Road, Kempsey NSW 2440 (02) 6563 1599 Nowra Hydro

Factory 1/5 Sefton Road, Thronleigh NSW 2120 (02) 9473 5000

15/The Crescent Street, Penrith NSW 2750 (02) 4732 2870

Northern Nursery Supplies Pty Ltd

423 Princess Highway, Rockdale NSW 2216 (02) 9567 8841Hyalite Moorebank

Retail Stores listed alphabetically by city in each state.

597 Tapleys Hill Road, Fulham SA 5024 (08) 8235 2004

Futchatec Distribution

4 Symonds St. Royal Park, 5014 (08) 8447-1122

Glandore Hydroponics

644 - 646 South Road, Glandore SA 5037 (08) 8371 5777

Greener than Green

52 - 54 Cliff Avenue, Port Noarlunga South SA 51 (08) 8386 2596

13 Research Road, Pooraka SA 5095 (08) 8260 2000 Hydro Heaven

Kane Motors-Hunt Road, Mount Barker SA 5251 (08) 8391 1880 Hydro Sales & Service

1 Salisbury Crescent, Colonel Light SA 5041 (08) 8272 2000 Hydro Technics

321 South Road, Croydon SA 5008 (08) 8241 5022 Hydro Warehouse

181 Seacombe Road, South Brighton SA 5048 (08) 8377 1200 Hydro World

40 Folland Avenue, Northfield SA 5085 (08) 8262 8323 Koko’s Hydro Warehouse

Unit 2/2 McGowan Street, Pooraka SA 5095 (08) 8260 5463

Larg’s Bay Garden Supply

239 Victoria Road, Largs Bay SA 5016 (08) 8242 3788

Martins Road Hydro

# 5- 353 Martins Road, Parafield Gardens SA 5107 (08) 8283 4011 Mitre 10 Drive In

152 Hanson Road, Mansfield Park SA 5012 (08) 8445 1813 New Age Hydroponics

135-137 Sir Donald Bradman Dr., Hilton SA 5033 (08) 8351 9100 Owen Agencies

17-19 Railway Terrace, Owen SA 5460 (08) 8528 6008 Professional Hydro

4/522 Grange Road, Fulham Gardens SA 5024 (08) 8353 0133 Professional Hydro

Shop 5/645 Lower North East Road SA 5075 (08) 8365 5172 Professional Hydroponics

113 Maurice Road, Murray Bridge SA (08) 8532 3441

Seaton Hydroponics

Greenhouse Superstore Lonsdale

129 Tapleys Hill Road Seaton SA 5023 (08) 82682636

Greenhouse Superstore Royal Park

44 Chapel St., Norwood SA 5067 (08) 8362 8042

35 to 37 Aldenhoven Road SA 5160 (08) 8382 0100 4 Symonds St. Royal Park SA 5014 (08) 8447 5899

Ground-Up Service Nursery

3 Copinger Road, Pt. Pirie SA 5540 (08) 8264 9455

Soladome Aquaculture & Hydro

South Coast Hydroponics

6/25 Gulfview Road, Christies Beach SA 5165 (08) 8384 2380 State Hydroponics

174 Semaphore Road, Exeter SA 5019 (08) 8341 5991

Tea Tree Gully Hydro

32 Famechon Cresent, Modbury North SA 5092 (08) 8264 9455 Two Wells Hardware

86 Old Port Wakefield Road, Two Wells SA 5501 (08) 8520 2287 Urban Grow Solutions

1/111 Main Sth Rd, O’Halloran Hill, S.A 5189 (08) 8322 0040 West Garden Centre

Peachey Road, Elizabeth West SA 5113 (08) 8255 1355 TASMANIA Advanced Hydroponics

26 Mulgrave Street, South Launceston Tas 7249 (03) 6344 5588 Ezy Grow

625 East Derwent Highway, Lindisfarne Tas 7015 (03) 6243 9490 Garden World

717 West Tamar Highway, Legana Tas 7277 (03) 6330 1177 ------------------------------------------

Barb’s Hydro and Nursery

Hydroware

15 Wallace Avenue, Interverloch Vic 3196 (03) 5674 2584

59a Lara Way, Campbellfield, Vic, 3061 (03) 9357 8805

87A Archer Street, Shepparton Vic 3630 (03) 5831 6433

Hyalite Airport West

5/ 411-413 Old Geelong Rd., Hoppers Cros. 3029 (03) 9360 9344

Bayside Hydroponics

5/9 Rutherford Road Seaford, VIC 3198 (03) 9775 0495Belgrave Hydroponics

5/ 60-68 Colby Drive, Belgrave Heights Vic 3160 (03) 9754 3712 Brew ‘N’ Grow

4 - 479 Nepean Highway, Edithvale Vic 3199 (03) 9783 3006 Casey Hydro

12 The Arcade Street, Cranbourne Vic 3977 (03) 5996 3697 Casey Hydro

78 Spring Square, Hallam Vic 3803 (03) 9796 3776Chronic Hydroponics

31 Anderson Street, Templestowe Vic 3106 (03) 9646 8133 Complete Garden Supplies

580 Ballarat Road, Sunshine Vic 3020 (03) 9311 9776 Discount Hydroponics

Green Acres Hydroponics

Unit 1 46-48 Bingalong Rd, Mornington, TAS 7018 (03) 6245 1066

-----------------------------------------Growers Choice

225 Main Road, Derwent Park Tas 7009 (03) 6273 6088 Hydroponics Systems

131 Main Rd, Moonah, TAS 7009 (03) 6278 3457

Hydroponic World

322 Bass Highway, Sulphur Creek Tas 7316 (03) 6435 4411 Organic Garden Supplies Tas

17 Don Road, Devonport Tas 7310 (03) 6424 7815

Tas Hydroponic Supplies

99 Lampton Avenue, Derwent Park Tas 7009 (03) 6272 2202

The Hydroponic Company

69 Charles Street, Moonah Tas 7009 (03) 6273 1411

The Hydroponics Company

289 Hobart Road, Kings Medow Tas 7428 (03) 6340 2222 VICTORIA

Albury Hydroponics / Cappers Hydroponics

62 Thomas Mitchell Drive, Springvale Vic 3171 61 (02) 6024 4029 All Seasons Hydroponics

3 Springvale Road, Springvale Vic 3171 (03) 9540 8000

Banksia Greenhouse and Outdoor Garden

530 Burwood Highway, Wantirna Vic 3152 (03) 9801 8070

18 Princes Hwy. Doveton VIC 3177 (03) 9792 2966 Echuca Hydroponic Nursery & Supplies

23 Ogilvie Avenue, Echuca Vic 3564 (03) 5480 2036 Echuca Pump Shop

128 Ogilvie Avenue, Echuca Vic 3564 (03) 5480 7080 Excel Distributors Pty Ltd

2/41 Quinn Street, Preston Vic 3072 (03) 9495 0083 F.L.O.W. Plants and Environments

66B Chapel Street, Windsor Vic 3181 (03) 9510 6832 Gardensmart

810-834 Springvale Road, Keysborough Vic 3173 (03) 9769 1411 Global Hydroponics

10 Knight Avenue, Sunshine Vic 3020 (03) 9356 9400 Greenleaf Hydroponics

9a Church Street, Traralgon Vic 3844 (03) 5176 0898 Greenleaf Hydroponics

Factory 7, Industrial Park Drive, Lilydale Vic 3140 (03) 9739 7311 GreenLite - Ringwood

Unit 4/504-506 Fullarton Road, Airport West 3042 (03) 9331 5452 Hyalite Bayswater

4/19 Jersey Road, Bayswater Vic 3153 (03) 9720 1946Hyalite Global

10 Knight Avenue, Sunshine North Vic 3020 (03) 9356 9400 Hyalite Westend

3 Third Avenue, Sunshine Vic 3020 (03) 9311 3510 Hydroponic Central

110 Dynon Road West Melbourne Vic. 3003 (03) 9376 0447 Indoor Garden Company

29 Glasgow Street, Collingwood Vic 3066 (03) 9416 1699 Impact Distribution

PO Box 2188, Salisbury Downs 5108 (08) 8250-1515JB Lighting 492 - 500 Neerim Road, Murrumbeena Vic 3163 (03) 9569 4399 Just Hydroponics Deer Park

Unit 11 29-39 Westwood Drive, Deer Park, VIC 3023 (03) 8390 0861 Just Hydroponics Geelong

Simply Hydroponics

Simply Hydroponics

8, 59-61 Miller St., Epping 3076 (03) 9408 4677

Sunlite Hydroponics

1/104 Shannon Avenue, Geelong West Vic 3281 (03) 5222 6730 Simply Hydroponics Pakenham

Factory 6/3-11 Bate Close Pakenham, Victoria 3810 03 5940 9047 Sunray Hydro

157 Tenth Street, Mildura Vic 3500 (03) 5023 6422 Supply Net International P/L PO Box 171, Highbury Vic 5089 (88) 264-3600 The Hydroponic Connection

397 Dorset Road, Boronia Vic 3155 (03) 9761 0662 Waterworks Hydroponics

Unit 1, 5 Brand Drive, Thomastown Vic 3074 (03) 9465 1455 WESTERN AUSTRALIA Accent Hydroponics

Hydroponic Solutions

1/1928 Beach Road, Malaga WA 6090 (08) 9248 1901 Hydroponic Warehouse

Guru Gardener

14 Molesworth St., New Plymouth 06 758 6661

Isabella’s Hydroponics

1083 S.H. 1 South Otaki 06 364 2206

66 Jambanis Road, Wanneroo WA 6065 (08) 9306 3028 Johnson’s Nursery Garden Centre

Unit 1, 21 Warman St. Neerabup WA 6031 (08) 9404 7155 One Stop Hydroponics

947 Beaufort Street, Inglewood WA 6052 (08) 9471 7000 Perth Hydroponic Centre

Midtown Hydroponics

Factory 1, 821B Howitt St., Wendouree Vic 3355 (03) 5339 1300 One Stop Sprinklers

1 Burwood Highway, Wantirna Vic 3152 (03) 9800 2177 Pam’s Home Brew & Hydroponics

61 McArthur Street, Sale Vic 3850 (03) 5143 1143

Grow 4 XS

Palms & Plants

Rear 24 Simms Road, Greensborough Vic 3088 (03) 9435 6425

175 Salisbury Highway, Salisbury S.A. 5108 (08) 8285 7575

Holland Forge Pty Ltd.

Prestige Hydroponics Pty. Ltd.

S 2.10 Level 2, 343 Little Collins St. Melbourne VIC Australia 3000 61 4 187 81083

Shop 1, 21 Hennessy Road, Bunbury WA 6230 (08) 9721 8322 Greenfingers World of Hydroponics

Albany Hwy & Kelvin Rd., Maddington WA 6109 (08) 9452 0546

Greenfingers World of Hydroponics

Unit C 14-16 Elliot Street, Midvale WA 6056 (08) 9274 8388 Greenlite Hydroponics

4/91 Wanneroo Road, Tuart Hill WA 6060 (08) 9345 5321

Growsmart Hydroponics

47768 South Coast Highway, Albany WA 6330 (08) 9841 3220 Hydro Nation

41A Rockingham Road, Hamilton Hill WA 6163 (08) 9336 7368

Cnr of Maunganui Rd & Tawa St., Mt Maunganui 07 575 4090 Switched on Gardener

Number 189 (Lower) Dent Street, Whangarei (09)438 0223

Reptile and Grow Store

Switched on Gardener

Southwest Hydroponics

Great Southern Hydroponics

Green Day Hydroponics

Switched on Gardener

Lot 12 Warton Road, Canning Vale WA 6155 1800 640 222

18/10 Norton Drive, Melton Vic 3194 (03) 9746 9256

Grow and Brew

Shop 4, 171-175 Abernathy Road, Belmont WA 6104 (08) 9478 1211

Aquaponics

Melton Hydroponic Supplies

Pet and Garden

14a Flexman Place, Silverdale Auckland 09 426 2095

Richo’s 4 Hydro

1/95 Dixon Road, Rockingham WA 6168 (08) 9528 1310

221 Waiwhetu Rd., Lower Hutt Wellington

Neerabup Organic & Hydroponic Supplies

Aqua Post

Creative Hydroponics

House of Hydro

10 Fitzgerald Ave., Christchurch 03 377 2507

Latrove Valley Home Brew Supplies

345 Sommerville Road, Footscray West Vic 3012 (03) 9314 0055

Otaki Hydroponics

30 Blencowe Road, Geralton WA 6530 (08) 9921 6016

Unit 7 - 117-119 Dixon Road, Rockingham WA 6168 (08) 9527 2245

8/13 Worcestor Bend, Davenport, WA 6230 (08) 9725 7020

15/69 Wiri Station Road, Manukau, Auckland 09 263 7560

317 Guildford Road, Maylands WA 6051 (08) 9371 5757

Unit 2B 7 Yampi Way, Willetton WA 6155 (08) 9354 2888

Living Jungle

3018 Gt North Rd New Lynn, Auckland 09 827 0883

Hydroponica

Unit 2/141 Russell Street, Morley WA 6062 (08) 9375 9355

Bunbury Alternate Growing Supplies

Easy Grow New Lynn

Easy Grow Manukau

Unit 7 36-38 Saunders street, North Geelong, VIC 3215 (03) 5278 6478

PO Box 802, Morwell Vic 3804 (03) 5133 9140

NEW ZEALAND

Unit 7/627 Wanneroo Road, Wanneroo WA 6065 (08) 9206 0188

Unit 7/22 Franklin Lane, Joondalup, WA 6027 (08) 9301 4462

291 Maroondah Highway, Ringwood Vic 3134 (03) 9870 8566

5 Hi-tech Place, Rowville Vic 3178 (03) 9764 1372

Shepparton Hydroponics

Lot 29, Pinjarra Road, Mandurah WA 6210 (08) 9534 8544 The Grow Room

Unit 159 Central Park Drive, Henderson (09) 837 1210 Unit 1/60 Ti Rakau Drive, Pakuranga (09) 576 0296

Switched on Gardener

Number 1c Sunshine Ave, Hamilton (07) 850 8351 Switched on Gardener

Number 513 Heretaunga Street West, Hastings (06) 876 7885 Switched on Gardener

Number 62 Kaiwharawhara Road, Wellington (04) 472 5265

1/1451 Albany Highway, Cannington WA 6107 (08) 9356 7044

Switched on Gardener

Bloem

Switched on Gardener

PO Box 1816, Subiaco WA 6008 (08) 9217 4400 The Watershed Water Systems

150 Russell Street, Morley WA 6062 (08) 9473 1473 The Watershed Water Systems

2874 Albany Highway, Kelmscott WA 6111 (08) 9495 1495 The Watershed Water Systems

1/146 Great Eastern Highway, Midland WA 6210 (08) 9274 3232 Tru Bloomin Hydroponics

7/36 Port Kembla Dr. Bibra Lake, WA 6163 (08) 9434 5118 Water Garden Warehouse

14 Drake Street, Osborne Park WA 6017 (08) 9443 7993

Unit 7/67 View Road, Glenfield (09) 443 0106 Number 1 Rata Street, New Lynn (09) 826 4444 Switched on Gardener

Number 57 Cavendish Drive, Manukau (09) 263 4336 Switched on Gardener

Number 427 Cameron Road, Tauranga (07) 579 9840 Switched on Gardener

Number 1060 Fergusson Drive, Upper Hutt (04) 526 3913 Switched on Gardener

Number 3 Pascoe Street, Nelson (03) 546 4769 Switched on Gardener

Number 9 Buckley Road, Linwood (03) 381 0937

Switched on Gardener

Number 143 Tuam Street, Christchurch CBD (03) 374 5682 Switched on Gardener

Number 313 King Edward Street, Dunedin (03) 456 1980

Maximum Yield | November/December 2012

51

DO YOU KNOW?

1.

In tomatoes alone, we have identified over 400 volatile aromatic compounds that contribute to overall flavour experience—and there are potentially many more to be discovered.

2.

While durable hydroponic media does not compost in the traditional way, it can be run through the process alongside organic material to form a pre-amended compost material.

The air around us contains roughly 200 to 300 ppm (or, 0.02 to 0.03%) CO2. Plants do well in this range, but we have learned that you can supercharge your garden by enriching the atmosphere in your grow room to 1,200 to 1,500 ppm (or, 0.12 to 0.15%)—however, keep in mind that anything above this can be harmful to plants and humans.

4.

5.

For fan and pad cooling to work at maximum efficiency, it is important to keep the growing area as airtight as possible.

Many commonly used rooting media are derived from naturally occurring substances; therefore, they contain some, or many, of the essential plant nutrient elements.

Ventilation is an essential component of evaporative cooling as the evaporation of water causes humidity levels to rise.

7.

9.

8.

The size and shape of the containers in which the medium is placed determine the amount of water that the media can hold.

Plant material grown with organic and chemical fertilisers can be composted.

Maximum Yield |  November/December 2012

6.

In warm climate greenhouses with mature crops, the rate of ventilation required to simply remove the heat from incoming solar radiation, supply fresh CO2 for photosynthesis and lower humidity from crop transpiration is often as high as one complete air exchange per minute.

A balance between air content and available water is one of the most important requirements of good media.

52

3.

10.

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To enter and for more details, visit | November/December maximumyield.com/contests.php 53 Maximum Yield 2012

ho se be c

COMING UP IN January-February Best Cleaning Practices: How to Get the Most Out of Your System Karen Wilkinson offers up some tips on how to keep keeping your system and growroom clean in order to get consistent, quality results.

The Science Behind Light Every garden (and its light requirement) is different, but the laws of physics apply equally to them all.

Creating a Small Space Oasis: Gardening for Apartment-dwellers Even though apartments have little or no space for gardening, that doesn’t mean people who live in these places can’t grow plants.

Plus: Hydroponic news, tips and trivia; hot new products; exclusive giveaways; Talking Shop and more!

Maximum Yield Australia (January/February) will be available in January for free at select indoor gardening retail stores across Australia and on maximumyield.com Subscriptions are available at maximumyield.com/subscriptions and maximumyield.com/digital-subscription

COMING UP ON THE WEB Final Stop of the 2012 Grow Like a Pro Tour Combines Indoor Gardening and Hydrolife Expo This world-class event will be a combination Indoor Gardening and Hydrolife Expo featuring leading experts from the hydro, snow, surf, skate and bike industries. Held at the beautiful Long Beach Convention Center for the third year running, this expo provides the ideal location with the perfect mix of culture and climate. Visit indoorgardenexpo.com PRO for complete event A LIKETOUR! details and to start planning your vacation.

W GRO

54

We’re happy to announce we’ve got special group flight rates with WestJet to our trade shows. Visit us online at indoorgardenexpo.com to receive the promo code.

Got Questions?

Get Answers.

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Maximum Yield | November/December 2012

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Maximum Yield | November/December 2012

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Maximum Yield |  November/December 2012