White Powdery Mildew (WPM) is a pretty irritating scourge. It starts out slow, and easy to fix, but can become widespread enough to wipe out an entire harvest! This is a living, breathing, angry flour like substance with an appetite for your cannabis like no other. Good news – if growers catch this in early stages, it’s totally reversible! But, only up to a certain point.
WPM is a fungus that reproduces both asexually AND sexually. This means it grows and feeds rapidly! It’s got two drives in life: make more powdery mildew, and eat your beautiful cannabis.
— How do you identify it?
This stuff is easy to spot – it looks like powder on yo’ leaves. Picture your fan leaves getting together and throwing down on some primo Colombian sugar. Then picture the hangover tomorrow when they can’t stop partying and eventually wither and die. This is WPM.
But really, it looks like flour coating the edges and eventually all over those nice dark green healthy leaves. It spreads quickly.
Besides having coke fiends for plants, there are several dangers: humidity creates the perfect environment for powdery mildew to grow. This means if some spores are prevalent among your plants, and you aren’t being careful to defoliate, or live in a naturally humid environment like Florida, or your grow room settings aren’t perfect (40-60% RH is recommended for young plants, and is also unfortunately the perfect setting for mildew), WIDESPREAD POWDERY MILDEW. Your buds will mold from the inside out with enough spores & humidity.
Oscillating fans provide a more arid environment, improving ventilation and humidity between leaves. Adequate lighting means less leaves squish together trying to reach their food source, which means less prime environments for mildew.
The easy treatment method (when caught early on) is simple:
Remove powdery mildew from leaves physically (paper towel + tap water works just fine.)
Dispose of said paper towels, because spores.
Two-fan minimum in grow area. Gently rustling leaves is all you need to radically improve WPM conditions.
Treat plant with IMK to eradicate any remaining spores, just before lights off for the day!