What Home Remedy Kills Gnats In Houseplants?. Olive oil is expensive and wee bit complex to make at home. How to get rid of fungus gnats in houseplants:
The soil will start to oxidize a few minutes after application. So the best way of naturally getting rid of gnats in plants is to replace the first layer of soil with sand or gravel. The fungus gnat will be killed by contact with hydrogen peroxide.
