Hydrogen peroxide (the standard 3% topical variety) can be used as a soil drench. Mix one part peroxide with four parts water, and pour it through the soil at the root zone until it begins to come out of the base of the pot. The peroxide kills fungus gnat larvae on contact. Neem oil is also an effective soil soak to combat fungus gnat larvae.

Generally a concentration of one tablespoon dish soap in a quart of water is strong enough to deter fungus gnats without bothering your plant.

Chamomile and cinnamon are powerful natural fungicides, so the logic was that by killing off the gnats� primary food source, it makes your plant soil less hospitable and therefore reduces population.

Fungus gnats are completely harmless to humans, since they can’t bite and don’t spread diseases. They can be a problem for houseplants, however, when their population explodes, and their larvae starts to feed on plants’ thin roots. Fungus gnats may also spread Pythium, a group of plant pathogens that causes “damping off” in seedlings.