How to Get Rid of Fungus Gnats on Houseplants

Stop watering as frequently and apply yellow sticky traps to catch adult gnats, then treat the soil with beneficial bacteria or hydrogen peroxide to kill larvae.

1. Starve the larvae now. Let the top 1-2 inches of soil dry out completely before watering again. Fungus gnats thrive in moist soil, so breaking this cycle starves their larvae. Check soil moisture by sticking your finger deep into the potting mix.
2. Trap adults fast. Place bright yellow sticky cards near affected plants at soil level. Adult gnats are attracted to yellow and will get stuck when they try to land. Replace traps every few weeks or when they're covered with gnats.
3. Deploy the bioweapon. Mix Bacillus thuringiensis israelensis (BTI) mosquito dunks or granules into your watering routine. This naturally occurring bacteria kills gnat larvae without harming plants. Follow package directions for dilution ratios.
4. Oxygenate and obliterate. Mix one part 3% hydrogen peroxide with four parts water. Pour this solution onto the soil until it drains from the bottom. The peroxide kills larvae and eggs while adding oxygen to the soil. Wait a week before regular watering resumes.
5. Start with clean soil. Remove the top inch of potting soil and replace it with fresh, dry potting mix. This eliminates many eggs and larvae while creating a barrier. Add a layer of sand or perlite on top to prevent adults from laying new eggs.
6. Keep soil breathing. Ensure pots have drainage holes and aren't sitting in standing water. Move plants to areas with better air circulation. Consider repotting severely infested plants in fresh, well-draining potting mix.