Fungus gnats live and thrive in the soil of houseplants. If you have a fungus gnat infestation and do not want to use commercial insecticides or pest strips, you may already have the solution to your problem in your house. A little cider vinegar in a container may be all you need to get rid of your fungus gnat problem for good. If the gnats in your house are too smart for the simple vinegar solution, a slightly more involved remedy involves judicious application of peanut butter along with the vinegar.
Pour a small amount of cider vinegar into your container. About 1 inch of liquid will suffice.
Place the container of cider vinegar near the infested houseplant. Fungus gnats should dive into it, as they are attracted to the smell. They will then drown.
Rub peanut butter on the inside of the lid to the bowl or container you are using for the cider vinegar.
Poke holes in the lid of the container with a knife. Make sure the holes are not very large. Secure the lid on top of the container, with both the vinegar and the peanut butter inside.
Strain the vinegar into a new container after you have attracted a bunch of fungus gnats with it. This will allow you to reuse it until your gnat problem is completely quashed.