> Fungus gnats only reproduce in the top layer of the soil I had a bad case of fungus gnats, but they were in the bottom of the soil. My pots had drainage hole

> Fungus gnats only reproduce in the top layer of the soil I had a bad case of fungus gnats, but they were in the bottom of the soil. My pots had drainage holes, and the gnats would fly in and out from there. Thankfully they were ZZ plants, which are fairly tough, so I'd only water once a month when the pots were bone dry, and after about 6 months the gnats finally faded away.