Views: 1 Author: Site Editor Publish Time: 2025-03-12 Origin: Site
Powdery mildew thrives in humidity levels between 50% and 90%, with optimal growth occurring around 70%–80% relative humidity. Unlike many other fungi, powdery mildew doesn't require high moisture levels or standing water to develop. Instead, it prefers warm, dry conditions with high humidity in the air but dry leaf surfaces.
Preventing powdery mildew in a cannabis grow room requires strict environmental control, good airflow, and proper plant spacing.
Keep humidity between 40-50% during vegetative growth and below 40% in flowering. Rationally irrigate and use dehumidifiers during cannabis growth and maturity. PREAIR is a professional dehumidifier manufacturer that provides grow room dehumidifiers with high quality and low price. Welcome to consult solutions.
Maintain temperature around 70-80°F (21-27°C) to discourage mildew growth.
Use a hygrometer to monitor conditions constantly.
Install oscillating fans to keep air moving around plants.
Use an exhaust fan with a carbon filter to remove stale air.
Space plants properly to prevent overcrowding and stagnant air pockets.
Avoid overhead watering; water at the soil level.
Run grow lights and fans in cycles that prevent condensation buildup.
Ensure good drainage to prevent excess moisture.
Spray organic fungicides like neem oil, potassium bicarbonate, or a diluted milk solution (1:9 milk-to-water ratio).
Apply a sulfur burner during the vegetative stage to kill spores (avoid in flowering).
Check plants daily for early signs of white powdery spots.
Remove infected leaves immediately and do not compost them.
Quarantine new plants before introducing them to your grow space.
