Answer: Fungus gnats are a royal pain. They fly in from outdoors so even if you get rid of your current population, you may find a whole new generation a few months from now. Fungus gnats feed and breed in moist potting soil so a barrier between the soil surface and the pests will control them. Use either a thick layer of pebbles or a layer of sand over the surface of your soil. Or, you can temporarily drape plastic wrap over the top of the pot, tucking it in around the stems of your plants so the gnats cannot access the potting soil. Remove it when you water and then replace it. It takes about 2 weeks to control fungus gnats. Or you can use a product called Gnatrol which is a soil drench. Best wishes with your gnat control project!
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