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Tiny bugs flying around my cannabis plants – fungus gnats?
There are tiny black flies buzzing around the soil surface of my plants. They're really small and seem to hang out near the top of the soil. I think they might be fungus gnats?
Are they harmful? How do I get rid of them? My plants are 3 weeks into flower.
3 Comments
Fungus gnats! The adults are harmless but their larvae eat roots.
Quick fixes:
- Let soil dry out more between waterings (larvae need moisture)
- Top-dress with diatomaceous earth (kills larvae on contact)
- Yellow sticky traps to catch adults
- Water with Mosquito Bits tea (BTi bacteria, kills larvae)
The BTi treatment is the most effective long-term solution. One application usually handles it within a week.
I had gnats in flower too. The sticky traps + letting soil dry out fixed it in about 10 days. Your buds won't be affected — the gnats are only interested in the soil.
Pro tip: add a layer of sand or perlite on top of your soil. Gnats can't lay eggs through it. Works as prevention for future grows too.
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