Preventing Powdery White Mildew on Cannabis

White powdery mildew, or WPM, is a very common but serious threat to cannabis plants. WPM can be easily spotted on young leaves of a cannabis plant and appears as a white or grey powdery-fuzzy substance. Once powdery mildew has infected a plant's leaves, it can easily spread to other parts of the plant - including buds making them unusable.

Small bumps or blisters on the top of fan leaves are a clear sign that WPM is developing - if your powdery mildew infestation is severe, you will smell rotting vegetation.

When WPM has infected your plants, there are limited solutions. Immediately separate visibly infected plants and closely analyze all surrounding plants to ensure WPM did not spread. Smoking and/or ingesting powdery mildew is unsafe and can result in dizziness, brain fog, fatigue, respiratory infections, and can even lead to lung disease.

The most effective way to avoid WPM is by prevention.

White powdery mildew shown on leaves.


CleanLeaf HEPA grow room air cleaner installed in a grow room.



There are three times that you're most likely to see mold on your cannabis plants - during the vegetative stage, the last few weeks of flowering, and drying and curing. Powdery mildew thrives in over-watered and overcrowded plants and high humidity environments - which is why it's important to keep clean air circulating.

Implementing HEPA grow room air cleaners will actively remove dangerous submicron particulate to prevent WPM and other molds from coming into contact with your crop. HEPA grow room air scrubbers draw contaminated air through a series of high-efficiency filters where the air is cleaned and released back into the grow room.

The CleanLeaf HEPA grow room air cleaner doesn't require any ductwork - the plug & play design makes it easy to set it and forget it. Easily hang the unit for immediate air filtration without loss of heat, AC, or valuable floor space!

To learn more about our HEPA grow room air scrubbers, reach out to our team, or request a free quote.