How to Get Rid of Fungus Gnats in Indoor Plants: Simple, Natural Solutions That Actually Work
- Tammy Johnson
- 5 days ago
- 4 min read
Written and edited by Tammy 18th Dec 2025
If you’ve ever watered your favourite indoor plant and been greeted by a cloud of tiny flying insects… welcome to the world of fungus gnats. They’re super annoying, but totally fixable.
Fungus gnats are one of the most common indoor plant pests, especially in warm, humid homes or potting mixes that stay damp for too long. Let’s walk through exactly what they are, why they show up, and how to get rid of fungus gnats naturally, without harsh chemicals.
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What Are Fungus Gnats?
Fungus gnats are tiny black flies (about the size of a fruit fly) that buzz around potting mix and settle on nearby surfaces.
The adults are mostly just a nuisance, but it’s the larvae in the soil that can cause the real trouble.
Fungus gnat larvae can:
• Eat organic matter in potting mix
• Damage young roots
• Cause stunted, droopy growth
• Increase plant stress and susceptibility to disease
They thrive in consistently damp soil, which is why indoor plant lovers often meet them at least once.
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Why Do Fungus Gnats Turn Up?
Fungus gnats appear when the conditions are perfect for them, and unfortunately, indoor plant pots often provide exactly that, especially as we head into the warmer months and start ramping up the watering routine.
Common causes:
• Overwatering
• Poor drainage
• Potting mix high in compost or unbroken-down organic matter
• Re-using old or contaminated soil
• Bringing home new plants with hidden larvae
The trick to winning the battle is fixing both the adults AND the larvae.
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How to Get Rid of Fungus Gnats
1. Let the Soil Dry Out (Your Most Powerful Tool)
Fungus gnats hate dry soil. Their eggs and larvae need moisture to survive.
Let the top 2–5 cm of soil dry out between waterings.
Most indoor plants will handle this just fine, and you’ll interrupt the gnat life cycle.
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2. Bottom Water Instead of Top Watering
Bottom watering keeps the surface drier, making it less appealing to adult gnats.
Fill a bowl or sink, let the pot soak for 10–20 minutes, and allow it to drain well.
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3. Use Sticky Traps for Adult Fungus Gnats
Bright yellow sticky traps are one of the quickest ways to stop adult fungus gnats reproducing.
Place traps:
• On the soil surface
• Hanging just above your plant
• Near windows or lights
They’ll catch dozens within days!
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4. Add a Layer of Sand or Fine Gravel
Creating a dry, gritty top layer makes it impossible for adult gnats to lay eggs.
Great options:
• Horticultural sand
• Decorative pebbles
• Fine aquarium gravel
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Home Remedies for Fungus Gnats (That Actually Work)
5. Cinnamon Powder (Natural Antifungal)
Sprinkle cinnamon on top of the soil and gently swirl it in.
Cinnamon helps reduce the fungus the larvae feed on, slowing their lifecycle.
It won’t fix a huge infestation on its own, but as part of a wholistic action plan, it’s works well.
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6. Neem Oil Soil Treatment
Neem oil disrupts the larvae and pupae in the soil.
Mix according to your bottle’s directions and apply as a soil soak.
Repeat weekly for 2–3 weeks until numbers drop.
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7. Hydrogen Peroxide Soil Flush (Safe When Diluted)
This sounds scarier than it is!
Use 3% hydrogen peroxide mixed at
1 part peroxide : 4 parts water
Pour onto the soil as you would a normal watering.
It kills larvae on contact and breaks down into oxygen + water.
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When Should You Repot?
Sometimes the infestation is so deep that the fastest solution is to repot.
Repot your plant if:
• You see masses of larvae near the drainage holes
• The soil smells sour
• The mix is old, dense or stays wet for days
Use a fresh, well-draining indoor potting mix and clean your pot before reusing.
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Fungus gnats are one of those pests every indoor gardener deals with at least once, but they’re also one of the easiest to get rid of with the right steps.
Dry soil, sticky traps, neem oil, cinnamon, and good drainage will have your babies gnat-free in no time!
Happy Gardening😘🪴
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