Marijuana Horticulture: The Indoor/Outdoor Medical Grower's Bible

humidity. If the grow room is too small for the barrel, move it to another room. The attic is a good place because it promotes good pressure. Place a siphon hose in the top of the tank, or install a PVC on/off valve near the bottom of the barrel. It is easy to walk off and let the barrel overflow. An inexpensive device that measures the gallons of water added to the barrel is available at most hardware stores. You can also install a float valve in the barrel to meter out the water and retain a constant supply.
    Drip systems deliver nutrient solution one drop at a time or in low volume, via a low-pressure plastic pipe with friction fittings. Water flows down the pipe and out the emitter one drop at a time or at a very slow rate. The emitters that are attached to the main hose are either spaghetti tubes or a nozzle dripper actually emitting from the main hose. Drip irrigation kits are available at garden stores and building centers. You can also construct your own drip system from component parts.
    Drip systems offer several advantages. Once set up, drip systems lower watering maintenance. Fertilizer may also be injected into the irrigation system (fertigation); naturally, this facilitates fertilization but gives the same amount of water and nutrient to each plant. If setting up a drip system, make sure the growing medium drains freely to prevent soggy soil or salt buildup. If you are growing clones that are all the same age and size, a drip system would work very well. However, if you are growing many different varieties of plants, they may need different fertilizer regimens.
    I interviewed several growers that loved the convenience and constant feeding-ability of their drip systems. All the growers irrigated (fertigated) with mild nutrient solution. They mixed the nutrient solution in a reservoir and pumped it through plastic feeder hoses. They also grew clones in smaller containers and kept root growth to a minimum by keeping the nutrients and the water in constant supply.
    A drip system attached to a timer disperses nutrient solution at regular intervals. If using such a system, check the soil for water application daily. Check several pots daily to ensure they are watered evenly and that all the soil gets wet. Drip systems are very convenient and indispensable when you have to be away for a few days. However, do not leave a drip system on its own for more than four consecutive days, or you could return to a surprise!
    Drip systems cost a few dollars to set up, but with the consistency they add to a garden, their expense is often paid off by a bountiful yield. Be careful! Such an automated system could promote negligence. Remember that gardens need daily care. If everything is automated, the garden still needs monitoring. All the vital signs: moisture, pH, ventilation, humidity, etc., still need to be checked and adjusted daily. Automation, when applied properly, adds consistency, uniformity, and usually a higher yield.
    One indoor grower I met was out of town for five consecutive days every week. He watered and fertilized his plants. He put containerized plants in a tray with 2-inch-tall (6 cm) sides and watered the plants from above until the tray was full of water. He left for five days, and the plants needed no watering while he was gone. He used regular potting soil and added about 10 percent perlite. His plants needed maintenance when he returned, but the plants grew quite well.
Misdiagnosed Disorders
    Many indoor garden problems, and to a lesser degree outdoor problems, are misdiagnosed as a lack of fertilizer. Often, disease and insects cause such problems. Other times, problems are caused by an imbalanced pH of the growing medium and water. A pH between 6.5 and 7 in soil and 5.8 to 6.5 in hydroponics will allow nutrients to be chemically available; above or below this range, several nutrients become less available. For example, a full point movement in pH represents a tenfold increase in either alkalinity or acidity. This means that a pH of 5.5 would be ten times more acidic than a pH of 6.5. In soil, a pH below 6.5 may cause a deficiency in calcium, which causes root tips to burn and leaves to get fungal infections and dead spots on foliage. A pH over 7 could slow down the plant’s iron intake and result in chlorotic leaves causing veins to yellow.

Heat stress makes calyxes stretch up and grow beyond a compact bud.

Light burned this leaf. It appeared only on one leaf under the light

Light burned this