If you’ve ever noticed tiny flies hovering around your plants’ soil, you’re not alone. Those little bugs are fungus gnats; harmless to humans, but frustrating for plant parents everywhere. They love moist soil and can multiply fast, laying up to 200 eggs in their short lifetime according to Penn State Extension, turning your peaceful plant corner into a buzzing annoyance.
The good news? You can get rid of them quickly with a few simple tricks — no harsh chemicals required. Here are 8 easy, effective ways to banish fungus gnats and keep your plants healthy.
What Are Fungus Gnats (and Why Are They on My Plants)?
Fungus gnats are small, mosquito-like insects that thrive in damp soil. The adults are mostly a nuisance, but their larvae can cause damage by feeding on organic matter and delicate roots.
If you spot them, isolate the affected plant right away. It’s much easier to treat one pot than to chase gnats across your entire plant collection.
1. Use a Safe, Plant-Friendly Insect Spray
Wondering if insect spray will work? It can, as long as you choose the right kind. Traditional insecticides often contain harsh chemicals that aren’t ideal for indoor use. Instead, look for biopesticides or natural formulations that target pests safely.
Try this: Bio Insecticide Indoor/Outdoor Concentrate from Arber uses biopesticides instead of synthetic chemicals, making it safe for your plants, pets, and home environment. Just follow the dilution instructions and apply directly to affected areas.
2. Let the Soil Dry Out
Fungus gnats love moisture, so drying out their habitat is one of the fastest ways to stop them.
Try these moisture-control tips for keeping fungus gnats away:
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Water wisely: Only water when the top inch of soil feels dry.
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Improve airflow: A small fan or open window can make a big difference.
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Use a dehumidifier: Helpful if you live in a naturally humid climate.
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Add a grow light: Grow lights can gently warm soil, helping it dry faster.
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Choose terracotta pots: They absorb excess moisture better than plastic ones.
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Give plants space: Avoid crowding; it traps humidity.
When the soil stays on the drier side, fungus gnats can’t thrive
3. Treat Soil with Neem Oil
Can neem oil actually get rid of fungus gnats? Yes, and it’s one of the most effective natural options.
Neem oil, made from the neem tree (Azadirachta indica), works by disrupting pests’ life cycles while staying safe for humans and pets. It kills larvae in the soil and deters adults from returning.
Mix a neem oil concentrate (like Safer Brand Neem Oil) with water according to the label, then pour or spray it onto the top layer of soil. Bonus: neem oil also helps prevent common plant fungi, so it’s a multitasker.
4. Try the Raw Potato Trick
It might sound odd, but raw potato slices can reveal how bad your infestation really is and help reduce it. "The reason this works so well in comparison to other pest repellent strategies is that it tackles the problem of larvae, not just the flies themselves," says staff writer at Homes & Gardens.
Fungus gnat larvae are drawn to the moisture and starch in raw potatoes. Cut a potato into ½-inch slices and place them on the soil surface. After a few hours, check the undersides — if you see small larvae, toss the slices and replace them with fresh ones.
Keep repeating until the larvae disappear. It’s a simple, chemical-free way to track your progress.
5. Use Sticky Traps to Catch Adults
If you’re seeing gnats flying around, sticky traps are your new best friend.
These bright yellow traps attract and capture adult fungus gnats before they can lay more eggs. Place them directly in the soil or near affected plants. They’re waterproof, long-lasting, and easy to remove when full — a low-effort way to cut down the adult population fast.
6. Add a Soil Top Dressing
Can covering the soil really stop fungus gnats? Absolutely. Since fungus gnats lay eggs in the top layer of soil, adding a barrier makes it harder for them to access it.
Add about a ½-inch layer of sand, gravel, or decorative pebbles over the soil. This keeps gnats from laying new eggs while still allowing water to flow through easily. Just make sure the surface is evenly covered with no gaps!
7. Set an Apple Cider Vinegar Trap
This DIY trick works surprisingly well.
In a small bowl, mix apple cider vinegar with a few drops of dish soap. Cover it with plastic wrap and poke small holes in the top. The gnats are attracted to the vinegar, crawl in, and can’t escape once they touch the soapy liquid.
It’s a quick, budget-friendly solution that pairs nicely with the other methods on this list.
This is often a trick for getting rid of fruit flies, but it can also help with catching fungus gnats. Image by The Spruce.
8. Introduce Beneficial Nematodes
For serious infestations, you can call in some natural, biological control reinforcements like beneficial nematodes. According to the UMass Extension, "Beneficial nematodes are relatively easy to use but must be applied properly in order to be effective."
These microscopic worms actively hunt and kill fungus gnat larvae in the soil without harming your plants. They come in a powder or liquid form that you mix with water and apply to your soil.
Just make sure conditions are right: nematodes need mild temperatures (60–90°F) and slightly moist soil to do their best work. Once established, they’ll quietly take care of the problem for you.
Keep Fungus Gnats Away for Good
Once your plants are clear, here’s how to prevent them from coming back:
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Avoid overwatering and keep soil slightly dry between waterings.
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Remove fallen leaves or debris from pots regularly.
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Quarantine new plants before placing them near others.
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Keep a few sticky traps up for early detection.
With the right mix of prevention and quick action, you can say goodbye to fungus gnats and hello to healthy, thriving houseplants.
