If you are growing organically, fungus gnats lay eggs in the soil, so you can sprinkle diatomaceous earth onto the soil surface. It feels like a white powder, but is made of microscopic shells that cut the larva to pieces when they hatch and try to move.

The silica content is a nutrient to plants too.

You can purchase it at some nurseries (call around, most don't carry it) or in pool supply stores.
Mustelid Reviewed by Mustelid on . Fungus Gnats Im pretty sure I have a fungus gnat problem, there are a ton of them, but only on a few plants, the ones with my buddies shitty soil in them, but one plant in particular is getting annihilated. Any products recommended for that? -C Rating: 5