How to Get Rid of Fungus Gnats

If you’ve noticed tiny flies hovering around your plants or crawling on the soil, you’re not alone. Those are fungus gnats, one of the most common (and annoying) houseplant pests. While they’re harmless to humans, they can damage your plant’s roots and stunt growth if left untreated.

Here’s how to identify, eliminate, and prevent fungus gnats.

What Are Fungus Gnats?

Fungus gnats are small, dark flying insects (about 1/8 inch long) that thrive in moist soil. Their larvae feed on organic matter and sometimes the delicate root hairs of your plants. They’re often mistaken for fruit flies, but fungus gnats stick close to the soil and prefer damp environments.

Signs You Have Fungus Gnats

Tiny black flies hovering near your plants or windows

Larvae (thin, white worms) visible in the top layer of soil

Yellowing leaves or slowed growth in affected plants

Soil that stays constantly damp or smells musty

Step 1: Stop Overwatering

Fungus gnats love moisture. Allow the top 1–2 inches of soil to dry completely between waterings. This interrupts their breeding cycle. Most houseplants (like your Monstera, Philodendron, and Pothos) actually prefer a slightly drier soil anyway.

Pro Tip: Water your plants from the bottom when possible to keep the soil surface dry.

Step 2: Trap the Adults

Use yellow sticky traps. They attract and capture adult fungus gnats, helping reduce the population quickly. Place them near the base of your plants or directly in the soil.

Step 3: Treat the Soil

Once adult gnats are trapped, it’s time to eliminate the larvae hiding in the soil. Try one of these natural remedies:

Hydrogen Peroxide Solution: Mix 1 part hydrogen peroxide (3%) with 4 parts water. Water your plants with the mixture once — it kills larvae on contact.

Neem Oil or Mosquito Bits: Both are safe, plant-friendly options that target larvae. Mix neem oil with water and use it as a soil drench every 7–10 days.

Step 4: Repot if Necessary

If the infestation is severe, gently remove your plant from its pot, rinse off the roots, and repot it in fresh, sterile, well-draining soil. Discard the old soil and clean the pot with soap and warm water before reusing.

Runo recommends using our Organic Indoor Potting Mix, designed to stay airy and discourage gnats.

Step 5: Prevent Future Infestations

Always use well-draining soil and pots with drainage holes

Avoid letting water sit in saucers

Quarantine new plants before introducing them to your collection

Add a layer of decorative sand, gravel, or moss to cover the topsoil — this blocks gnats from laying eggs

Final Thoughts

Getting rid of fungus gnats doesn’t have to be stressful. With the right care routine and preventive steps, you can protect your plants and keep your indoor jungle thriving.

At Runo Plants, we believe plant care should be simple, natural, and rewarding. Explore our Plant Care Tools and Soil Mixes to help your plants stay healthy, pest-free, and beautiful all year long.