Adding a 1-inch layer of sand or oyster shells on top of the soil prevents adults from laying eggs and keeps the surface dry.
Getting rid of gnats effectively requires a dual approach: to stop them from breeding and treating the breeding grounds (soil or drains) to kill larvae and eggs. Best-Reviewed Solutions by Gnat Type 1. Houseplant (Fungus) Gnats These thrive in moist soil and decaying organic matter. how do get rid of gnats
A mixture of 1 part 3% hydrogen peroxide to 4 parts water kills larvae on contact when used for watering. Adding a 1-inch layer of sand or oyster