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White powder on cannabis leaves – powdery mildew help!
Found white powdery patches on several fan leaves this morning. Pretty sure it's powdery mildew. Plant is in week 3 of flower.
Is my crop ruined? Can I still save it? What should I spray in flower?? Panicking a bit here.
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3 Comments
Experienced1mo ago
DON'T panic. Powdery mildew in week 3 of flower is treatable.
**Immediate steps:**
1. Remove the worst affected leaves (bag them, don't shake spores around)
2. Increase airflow immediately — add another fan
3. Drop humidity below 50%
4. Spray with potassium bicarbonate solution (1 tbsp per gallon) — safe in flower
**DO NOT spray neem oil in flower** — it affects taste.
Your crop is NOT ruined if you act fast. The buds that aren't affected will be fine.
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Experienced1mo ago
Adding to Dave's advice: after harvest, do a bud wash. 3 buckets: hydrogen peroxide water, lemon juice water, plain water. Dip and swish. This removes any remaining PM spores and is totally safe. I do this for all outdoor harvests.
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Experienced1mo ago
Prevention for next run: keep humidity under 55% in flower, ensure good air circulation, and defoliate properly so air can move through the canopy. PM thrives in stagnant, humid air.
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