Marijuana Horticulture Fundamentals. K of Trichome Technologies

      Storage for lights.

      Before you introduce plants to a new environment, there are a few precautionary measures to take.

      Pyrethrumbombs may be used in your empty chambers to eliminate unwanted pests.

      Chlorine bleach, mixed at ten parts water to one part bleach, can be used to clean all surfaces inside the chamber and in hydroponic and aeroponic systems between harvests. Be sure to rinse off all trace amounts of bleach solution after cleaning.

      Food grade 27% hydrogen peroxide may also be used to decontaminate growing chambers, mixed at ten parts water to one part hydrogen peroxide.

      Note: when undertaking this final precaution, spray either the bleach / water or peroxide / water (Caution! Never mix both!) solution from a 5-gallon pressurized garden sprayer (peroxide does not smell and leaves no harmful residue). Spray walls, ceilings, floors, all cleanable areas and surfaces. Electrical components should be wiped down with a washcloth dampened with the solution. Always wear rubber gloves, a protective breathing apparatus / mask, and eye protection when spraying bleach, and be sure to keep the area very well ventilated. (Flora Kleen by General Hydroponics is a fantastic hydroponic disinfectant. It both sterilizes hydro systems and eliminates salt / mineral deposits.

      ONA is a good chlorine bleach alternative. It is used for disinfection and general cleanliness, and does not harm plants or animals. It does not emit toxic fumes. It can be used for sterilizing entire systems and growrooms and eliminating fungi and bacteria even in mid-growing cycle (or, of course, when your grow area is empty). ONA also eliminates mineral deposits.

Greenhouse

      Simplistic setups work best, and this greenhouse—a representative setup—demonstrates just that. The medium here is ⅓ Fox Farms “Ocean Forest” soil, ⅓ vermiculite, and ⅓ perlite, mixed with water-retaining crystals. The containers are 2-gallon, and the plants in this picture, at three- to four feet tall in the flowering stage, need to be watered every other day. The nutrients used in this photo were General Hydroponics Flora Series as well as other amendments, as discussed later in the book.

      In most environments plants cannot be placed outdoors in mid-Spring because temperatures are still too low for optimum growth. A greenhouse will keep the plants warm, day or night, even in cold or rainy conditions. Greenhouse-grown plants vigorously thrive. The clear plastic covering the greenhouse intensifies the sun and can elevate the temperature inside to roughly 85°F on a day when it is only 65°F outside—a temperature differential of 20°F.

      When growing in a greenhouse you can produce three or even four crops per year, rather than one or two, as you can outdoors, uncovered. We place vegetated (approximately 24 inches tall) plants out into the greenhouse on April 20th and immediately induce flowering via light deprivation. (This deprivation is accomplished by using 6mm plastic that is black on one side and white on the other, with which we completely cover the greenhouse.) When the plants are fully mature and harvested, new, vegetated plants replace them immediately, and we repeat the cycle without losing a day of growth. And so on, repeating as we do in the symbiotic rotation process. In this way we get three crops by the first week of October.

      When it starts to rain, we place industrial-use large dehumidifiers in the greenhouse to prevent powdery mildew and botrytis (gray bud mold); we also tightly close all of the doors in order to keep out the rain. On overcast or rainy days we augment with supplemental lighting. For example, in a 10 × 10-foot greenhouse we use two 600-watt metal halide and two 600-watt sodium halide lights, as one might indoors, which has the added benefit of raising the interior temperature to desirable levels on cold days. With the doors sealed, the greenhouse must still be allowed to ventilate to keep oxygen and CO₂ levels in proper proportions.

      Buds that are produced in a greenhouse are more like indoor buds than outdoors—they are denser, have more THC, etc.—because you have more control of the environment. There are lots of variables. For example, on warm days the doors at each end of the greenhouse are opened and both walls are rolled up and secured using bungee cords. Large oscillating fans are good to mount, to keep the air moving when the doors are closed and the sides rolled down. You must also install intake and exhaust fans.

      Cover the greenhouse at night—you must have complete darkness inside to achieve optimum results. Try large sheets of 6mm Visqueen, white on one side and black on the other. The white side reflects heat off of the outside of the greenhouse and the black side absorbs heat on the inside. The cover is what allows you to induce flowering during months of extended sunlight.

      These plants were two feet tall when placed into this 8×10 greenhouse in early August in Northern California. Then, due to fewer hours of available light, they immediately began flowering.

      Photos: K