How to Get Rid of Gnats in Your House (DIY Guide)

When people say "gnats," they usually mean one of three things:

• Fungus gnats — Tiny black flies hovering around houseplants. They breed in the damp soil of overwatered plants. This is the most common indoor "gnat."
• Fruit flies — Tiny tan/brown flies near fruit, trash, and drains. We have a separate detailed guide for these.
• Drain flies — Fuzzy, moth-like flies near bathroom drains. We have a separate detailed guide for these too.

This guide focuses primarily on fungus gnats, since they're the most commonly misidentified "gnat" and the one most people are searching for when they Google "gnats in my house."

• Yellow sticky traps — Small sticky cards on stakes that you insert into plant soil. Fungus gnats are attracted to yellow and get stuck.
• Hydrogen peroxide (3%) — The standard pharmacy kind. Used to kill larvae in soil.
• Sand or decorative pebbles — For topping soil to prevent egg-laying.
• Apple cider vinegar — For trapping adult gnats.
• Dish soap — For vinegar traps.

Step 1: Identify Your Gnat

Look at where they're congregating:

• Around houseplants? → Fungus gnats. Continue with this guide.
• Around fruit or trash? → Fruit flies. See our fruit fly guide.
• Near drains, fuzzy and moth-like? → Drain flies. See our drain fly guide.

Step 2: Let the Soil Dry Out

Fungus gnats breed in moist soil. The simplest and most effective step is to let the top 1–2 inches of soil dry out completely between waterings. Most houseplants actually prefer this anyway — overwatering is the #1 killer of houseplants and the #1 cause of fungus gnats.

Stick your finger an inch into the soil. If it's damp, don't water. Wait until it's dry to the touch before watering again.

Step 3: Treat the Soil

Mix one part 3% hydrogen peroxide with four parts water. Water your plants with this solution. The hydrogen peroxide kills fungus gnat larvae in the soil without harming the plant. You'll see some fizzing — that's normal. Do this for 2–3 watering cycles.

Step 4: Trap the Adults

Insert yellow sticky traps into the soil of affected plants. The bright yellow color attracts adult fungus gnats, and they stick to the adhesive. Replace traps when they're full. You can also set out small bowls of apple cider vinegar with a drop of dish soap near plants to catch adults.

Step 5: Prevent Re-infestation

Top the soil of your houseplants with a ½-inch layer of coarse sand, decorative pebbles, or perlite. This physical barrier prevents adult gnats from reaching the soil to lay eggs, breaking the life cycle.

• Don't overwater houseplants — This is the cause of 90% of fungus gnat problems. Let soil dry between waterings.
• Use pots with drainage holes — Standing water in pot saucers creates the wet conditions gnats love. Empty saucers after watering.
• Use a soil topper — Sand, pebbles, or perlite on top of soil prevents gnats from reaching the soil to lay eggs.
• Inspect new plants before bringing them inside — Fungus gnats often hitchhike on nursery plants. Check the soil surface for tiny flies before buying or quarantine new plants for a week.
• Store unused potting soil in sealed containers — Open bags of potting soil in garages and sheds can breed fungus gnats.

• Spraying flying gnats without treating the soil — Killing adults in the air is pointless if larvae are still developing in the soil. The soil is the source — treat it.
• Overwatering because "the plant needs it" — Most houseplants do better slightly underwatered than overwatered. If you have gnats, your plant is almost certainly being watered too often.
• Confusing fungus gnats with fruit flies — They look similar but breed in different places. If your traps near plants aren't catching anything, the flies might be fruit flies breeding in your kitchen. Check both areas.