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

agent. Specially designed paints for damp conditions contain a fungicide and are attracted by moisture. When applied to a damp, cracked basement wall, the paint is drawn into the moist crack. Remove all mold from the walls by washing it a with bleach solution before painting with fungusresistant paint. Cleanliness and climate control are the keys to preventing fungi. Few clean, well ventilated grow rooms have problems with fungi. In contrast, every dingy, dank, ill-kept indoor garden I have seen had fungal problems and yielded a substandard harvest.
    Install a vent fan(s) large enough to remove moist air quickly and keep humidity at 50 percent or less. A vent fan is the easiest and least expensive humidity control device available. CO 2 generators produce humidity-increasing water vapor as a by-product. Dehumidifiers are relatively inexpensive, readily available at discount stores, and do a good job of keeping humidity under control in enclosed grow rooms. Dehumidifiers draw extra electricity, and the condensed water must be removed daily. Wood, coal, and electric heat all dry and dehumidify the air. Most air conditioners can be set to a specific humidity level. If the grow room(s) have a central heating/air-conditioning vent, the vent can be opened to control temperature and lower humidity.
Control
    Prevent fungus by controlling all the factors contributing to its growth: remove hiding places, keep room clean, lower humidity to 50 percent, and keep the air well-circulated. If prevention proves inadequate and fungi appear, advanced control measures are necessary. Carefully remove and destroy dead leaves. Wash your hands after handling diseased foliage. If the problem attacks one or a few plants, isolate and treat them separately. Remember, fungi can spread like wildfire if the conditions are right. If they get a good start even after all preventive measures are taken, do not hesitate to take extreme control methods including spraying the entire garden with the proper fungicide.
Gray Mold (Botrytis), a.k.a. Bud Mold
    Identify: Gray mold is the most common fungusthat attacks indoor plants and flourishes in moist temperate climates common to many grow rooms. Botrytis damage is compounded by humid (above 50 percent) climates. It starts within the bud and is difficult to see at the onset–grayishwhitish to bluish-green in color– Botrytis appears hairlike and similar to laundry lint in moist climates. As the disease progresses, the foliage turns somewhat slimy. Damage can also appear as dark, brownish spots on buds in less humid environments. Dry to the touch, Botrytis -affected area often crumbles if rubbed. Gray mold attacks countless other crops, and airborne spores are present virtually everywhere. While most commonly found attacking dense and swelling flower buds, it also attacks stems, leaves, and seeds, causes damping-off, and decomposes dry, stored bud. It is also transmitted via seeds.
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Logical Progression of Fungus Control
    Prevention
    Cleanliness
    Low humidity
    Ventilation
    Removal
    Copper, lime sulfur sprays
    Specific fungicide
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    Damage: Watch for single leaves that mysteriously dry out on the buds. They could be the telltale signs of a Botrytis attack inside the bud. Constant observation, especially during the last two weeks before harvest, is necessary to keep this disease out of the garden. Flower buds are quickly reduced to slime in cool, humid conditions or unsmokable powder in warm, dry rooms. Botrytis can destroy an entire crop in seven to ten days if left unchecked. Stem damage– Botrytis starts on stems and not buds–is less common indoors. First, stems turn yellow and cankerous growths develop. The damage causes growth above the wound to wilt and can cause stems to fold over. Transported by air, contaminated hands, and tools, gray mold spreads very quickly indoors, infecting an entire grow room in less than a week when conditions are right.
    Control: Minimize Botrytis attack incidence with low humidity (50 percent or less), ample air circulation, and ventilation. Grow varieties that do not produce heavy, tightly packed buds that provide a perfect place for this fungus to flourish. Cool (below 70°F [21°C]), moist climates with humidity above 50 percent are perfect for rampant gray mold growth. Remove dead leaf stems, petioles, from stalks when removing damaged leaves to avoid Botrytis outbreaks, which is often harbored by dead, rotting foliage. Increase ventilation and keep humidity