Fungus gnats are tiny, dark-winged insects that can be a nuisance in indoor and outdoor plants, thriving in moist, rich soils where they feed on fungi, decaying plant material, and plant roots. While adult gnats are mostly harmless, their larvae can damage young seedlings or weak plants. Here are effective strategies to eliminate fungus gnats and protect your plants.

1. Reduce Soil Moisture

Fungus gnats thrive in wet soil, so reducing watering frequency can help deter them. Allow the top inch of soil to dry out before watering your plants again. This not only discourages gnats but also promotes healthier root growth in many plant species.

2. Use Yellow Sticky Traps

Yellow sticky traps are an effective way to catch adult fungus gnats. Place the traps near the affected plants, or stick them in the soil. The adults are attracted to the color yellow and will stick to the traps, reducing the overall gnat population.

3. Apply Diatomaceous Earth

Diatomaceous earth is a non-toxic powder made from crushed fossilized algae. It acts as a natural abrasive that cuts through the insects’ exoskeletons, causing them to dehydrate and die. Sprinkle diatomaceous earth on the top layer of your plant’s soil to kill larvae and deter adults.

4. Change the Soil

If an infestation is severe, it may be necessary to repot the plant. Remove as much of the old soil as possible from the roots, and replace it with fresh, sterile potting mix. This can remove a significant portion of the larvae and eggs.

5. Use Hydrogen Peroxide

Mixing a solution of hydrogen peroxide and water can help kill larvae on contact without damaging your plants. Use a solution of one part 3% hydrogen peroxide to four parts water, and water the soil with it. The extra oxygen in the hydrogen peroxide will kill the larvae and also help aerate the soil.

6. Introduce Beneficial Nematodes

Beneficial nematodes are microscopic worms that prey on fungus gnat larvae. They can be applied to the soil and are safe for plants, humans, and pets. These nematodes actively seek out larvae, entering their bodies and releasing a bacterium that kills them.

7. Cinnamon Solution

Cinnamon has antifungal properties that can kill the fungus which the gnats feed on, reducing their food source. Make a cinnamon solution by mixing one tablespoon of cinnamon in four cups of water and let it steep overnight. Strain and spray the solution on the plant soil to help reduce fungal growth.

8. Maintain General Plant Health

Keeping your plants healthy is one of the best ways to prevent any infestation. Healthy plants are more resistant to pests and diseases. Ensure your plants have proper light, and nutrients, and are in suitable soil and environmental conditions for their species.


Fungus gnats can be more than just a nuisance; they can be harmful to your plants if left unchecked. By implementing these practical strategies, you can effectively control and eliminate fungus gnat populations in your indoor garden. Regular monitoring and maintaining the right balance of moisture and plant care will keep your plants healthy and free from these pesky insects.

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