[brown_thumb]

My worst infestation was in a 18L bucket with soil but no plants. I did have five 100mm diameter coconut fiber pots sitting on top of that soil though. Those small pots were keeping the top 30mm of soil moist in the bucket. I moved the pots and dozens of gnats went flying. I disturbed the top 12mm of soil and hundreds of the little buggers went flying. I let them settle back in then drenched that bucket with a 4 liters of water with 60ml of neem oil plus 240ml of 3 percent H2O2. Of course, the drench fizzed like crazy but the next day all the gnats were gone. I was comfortable using that much H2O2 because the bucket had no plants.

I drenched the other buckets and the small pots with the same mixed but with one fourth as much H2O2.

Since then I've read that some people drench their buckets with live plants with a 50:50 mix of 3 percent H2O2:water. That seems awfully strong. Won't that burn the roots of the plants? Most references I see recommend 100ml of 3 percent H2O2 per 4L of water.