45 STARTING A SIX PLANT MEDICAL GARDEN
FOLIAR FEEDING
I recently got my medical marijuana card and want to start a 6-plant garden. I have a flower area 140 cm x 110 cm x 170 cm tall, lit with a 400w HPS. Is that enough light? Dan Your garden has an area of about 1.5 square meters (M2). To grow high quality buds, plants require an adequate amount of light. Varieties differ in the intensity of the light they need to produce bountiful yields of high quality buds. Indica type plants require at least 500 watts per M2. Indica-Sativa hybrids need at least 575 watts. Sativa-Indica hybrids require about 650 watts per M2.
Ed Rosenthal is recognized worldwide as a leading authority on marijuana. In his 30-plus years as America’s “guru of ganja” he has written or edited more than a dozen books about marijuana cultivation and social policy that cumulatively have sold over one million. His first book, Marijuana Grower’s Guide, is the only title on marijuana cultivation to be reviewed by The New York Times Book Review. After almost two decades, his Ask Ed advice column continues to answer questions on all matters of marijuana from readers around the world.
Use high-pressure sodium (HPS) lamps with reflectors that direct the light down to the plants. If your garden is filled with Indicas, use a minimum of 750 watts. Lamps of this wattage are not generally available. Instead, use two 400-watt lamps, or increase the yield by supplying more light. If they are available in your area, switch to a 1000-watt lamp.
Is foliar feeding necessary? Brinka No. Plants can use their roots to deliver all the nutrients necessary for growth. However, they can absorb nutrients though their leaf stomata. These pore-like openings are used to exchange gasses such as oxygen and carbon dioxide and to regulate temperature and turgidity through transpiration and water absorption. If the water contains dissolved nutrients they are also absorbed. There are several advantages to foliar feeding to supplement root feeding. First, the nutrients are used as much as 20 times more efficiently than when they are provided through the roots. They get directly to the plants. With root feeding only a small portion of the available nutrients are used. Another advantage is that it gets to the plants much faster. This is especially helpful when there are indications of a nutrient deficiency.
For the Indica-Sativa hybrids about 900 watts of light are required. There are no 900-watt lamps so you could use either a 400 and 600-watt lamp or a 1000watt lamp if they are available.
Generally speaking you can dilute the nutrient solution to 25% and spray the leaves until they drip. Gardeners often spray the plants with compost tea, which provides available nutrients and also coats the leaves with beneficial micro-organisms that protect it from pathogens. If there is a dark period in the light regimen, spray in the early part of the lit period. Don’t spray more than once a week. Don’t spray after the first four weeks of flowering. You can use less fertilizer in the water/nutrient solution since the plants are getting some directly to the leaves.
The Sativa-Indica plant garden requires a minimum of 1050 watts. You could skimp a little by using 400 and 600-watt lamps together or a single 1000-watt lamp. The plants produce more with more light so you might consider two 600-watt lamps.
Before trying this on your whole garden try it on a plant, or a part of a plant, first. Make sure to be a careful observer. If the plants are doing well continue, but if the plants react poorly to it, try another approach. One common problem is the water/nutrient solution is too concentrated. Try a more dilute solution.
LOW STRESS TRAINING What is LST? Buck LST, short for low stress training, is a technique used to keep plants at a low height and to fill out the canopy. It can be used indoors or out. Auxin is a growth hormone produced by the growing tip that inhibits the growth of side branches. A common way of stopping its production is to cut off the top of the growing tip, Then the side branches, now uninhibited, grow in a rosette around the cut tip. LST inhibits auxin production by bending the main branch, including the growing tip, so it is in a sideways position. As it continues to grow it is trained to continue horizontal growth. The side branches exhibit gravitropism; they orient themselves based on gravity. Since the stem is horizontal the branches start growing vertically. Each branch becomes a vertical stem. Keeping the main stem horizontal saves a lot of vertical space so it is convenient to use when it is at a premium. This is not its only advantage. It is an excellent way to grow large plants. Each of the side branches off the main stem becomes the equivalent of a vertical main stem. The single plant can spread out and become much larger than it would have if the main stem had been growing vertically. There are many ways to keep the stem horizontal. Stakes, screens, and ties are often used. Indoors, the stem is often bent in a spiral within the container to conserve space within the canopy. However, in some circumstances it may be more convenient to keep the stem horizontal and straight. The advantage of that is that the new vertical stems line up in a straight row. Other advantages are that the plant does not grow as tall as it would have untrained, and does not have the stereotypical symmetrical canopy found in both top pruned and unpruned plants. Outdoors, to grow the largest plant possible, start it early, perhaps under lights indoors. Use supplemental lighting to prevent flowering. Set the light cycle so it breaks up the dark period for a few minutes several times each evening. Give the plant LST so it has a lot of vertical “stems”, each ready to produce side branches. Then let it grow out. A similar technique is grow a plant in a container without pruning its top until it reaches a certain height, then turning it sideways so the main stem is horizontal. The container has to be modified so the roots can be watered from the new top and drained from the new bottom. The new side, which was the open top, must be sealed. The branches that were growing sideways will reorient themselves vertically and grow their own side branches.
Air cooling misters and mister fans (pictured) are used to lower the temperature of an outdoor space. Both produce micro particles of water, which quickly evaporates, cooling the air as much as 10 degrees.
