Skip to main content

How to get rid of fungus gnats: 5 ways to eliminate your gnat problem

Tips to get rid of fungus gnats and keep them away

As far as houseplant pests go, fungus gnats aren’t necessarily the worst critters to linger around your plants, but they can be quite the nuisance. They typically feast on soil infected with fungal or bacterial diseases, occasionally feeding on rotting roots.

Really, gnats only become problematic when they start to multiply — and once they multiply, they can multiply fast. While it might not live for more than two weeks, an adult fungus gnat can lay up to 300 eggs, making it imperative that you treat an infestation as soon as you notice it.

Difficulty

Moderate

Duration

15 minutes

What You Need

  • Sterile, soilless potting mix

  • Yellow sticky traps

  • Mosquito bits

  • Apple cider vinegar

  • Cup

  • Plastic wrap

  • Hydrogen peroxide

  • Neem oil

It’s easy to see just how problematic gnats can become, so how can you eliminate them? We'll go over tips on how to get rid of fungus gnats and prevent these pests from taking over your home, and we'll break down tried-and-true solutions for getting rid of them.

Fiddle leaf fig

What to do when fungus gnats start attacking your plant

While they’re harmless, fungus gnats can be indicative of a more serious problem. The number-one culprit behind fungus gnats is — drumroll please — overwatering! True to their name, fungus gnats often feed on fungus in the soil that can grow from overwatering and root rot. When you see them hovering around a specific plant, this may be a sign that you need to cut back on watering that plant.

Step 1: Isolate the affected plant from the rest of your collection to prevent the gnats from laying eggs elsewhere.

Step 2: Repot the affected plant into fresh soil, removing as much of the infected potting mix as possible. Replace it with a sterile, soilless mix if you can — organic amendments often attract these flying bugs.

Step 3: When you water your plants, use a method such as bottom watering to ensure you never let your plant sit in water.

houseplant collection

Solutions for getting rid of fungus gnats

After doing some damage control for your plants, it’s time to attack the fungus gnats themselves. Luckily, you can easily access solutions for fungus gnats since they’re a pretty common problem. You might even be able to grab remedies from your kitchen or medicine cabinet!

the best sticky traps for flies and flying insects fly trap

Solution 1: Yellow sticky traps

Yellow sticky traps aren’t the most subtle means of getting rid of fungus gnats, but they are effective. Adult fungus gnats will fly right to them and get stuck. While the traps can become unseemly over time, they will stop the gnats from reproducing. Yellow sticky traps for houseplants are easy to access as well — you can often find them in the pest control area of your local garden center.

Plant fertilized with pellets

Solution 2: Mosquito bits

Bacillus thuringiensis, or Bt, is used in a popular product called Mosquito Bits, which, in spite of its name, will also help you get rid of fungus gnats. Bt is essentially a bacteria that kills fungus gnats but is considered safe for humans and pets. Mosquito pellets are very effective, as they systematically kill larvae in the soil.

Step 1: If using Bt in pellet form, sprinkle the pellets directly onto your soil.

Step 2: If preferred, you can also soak the pellets inside your watering can to release the bacteria into the water. Pre-soaking allows the bacteria to travel more quickly to the roots, where the fungus gnats are likely feasting.

Glass bottle labeled vinegar on table

Solution 3: Apple cider vinegar

All you need for this one is apple cider vinegar, a clear cup, and plastic wrap.

Step 1: Fill a cup approximately one-third of the way with vinegar.

Step 2: Cover the top of the cup with plastic wrap and poke a small hole in the foil top. Adult gnats will fly into the vinegar through the small hole and eventually drown.

young woman watering plant using colour plastic can

Solution 4: Hydrogen peroxide

The next time you water a plant infested with fungus gnats, test out a hydrogen peroxide solution. While hydrogen peroxide might not be as effective as other suggestions on this list, it’s worth a shot since it’s probably already in your medicine cabinet! And while you can use a hydrogen peroxide solution as a spray on stems and leaves, it’ll work better in the growing medium because this is where eggs typically hatch.

Step 1: Create a mixture of one part 3% hydrogen peroxide and four parts water.

Step 2: Water affected plants with the hydrogen peroxide mixture, soaking the plant to kill larvae lurking in the soil. Don’t worry if the soil starts to fizz, as this is what happens when hydrogen peroxide breaks down.

Neem oil

Solution 5: Neem oil

Diluted neem oil is one of the most versatile products for dealing with pests. You can usually find it online or at your local garden center for use on plants. Whether you have scale, thrips, or gnats, it’s definitely convenient to have neem oil lying around to manage pests. Neem oil works by stopping insects from mating and eating, so they eventually die. The drawback with neem oil is that it’s usually a foliage spray, so you probably won’t be able to get it down to the roots where gnats and their larvae attack near rotting roots.

While not necessarily harmful, fungus gnats can quickly grow out of control and may also indicate an overwatering issue with your houseplants. To prevent fungus gnats, key preventative measures include never letting your soil get waterlogged and avoiding organic matter in your soil. If you do find your indoor jungle becoming a home to gnats, there are plenty of solutions out there to get rid of them. With a cup of apple cider vinegar or a sprinkle of mosquito bits, you’ll be on your way to getting rid of those pesky fungus gnats once and for all.

Editors' Recommendations

Stacey Nguyen
Stacey's work has appeared on sites such as POPSUGAR, HelloGiggles, Buzzfeed, The Balance, TripSavvy, and more. When she's…
The best sprays to keep pests off your delicate hibiscus plants
Safe and effective sprays for your hibiscus
Close-up of a red hibiscus flower

Garden pests can cause a lot of damage to your plants, by chewing holes in them, as well as spreading diseases. There are a lot of ways to get rid of them and keep them away for good, but many insecticides and pesticides include harsh chemicals that are not good for the environment. On top of that, some plants, like hibiscuses, are too sensitive for sprays like that! If you need help keeping pests away from your hibiscus plants, here’s what you need to know about insecticide for hibiscus.

Why are specialized sprays so important?
Insecticide or pesticide sprays have a job to do. They’re made specifically to kill insects and keep them away from your plants. Most plants can withstand the chemicals used in these sprays without issue, but some plants, like hibiscus, are particularly sensitive.

Read more
Black spots on roses are signs of a fungus – here’s how to get rid of it
Follow these tips to treat your black spots on your roses
A rose plant with bright yellow blooms

If you’ve started noticing some black spots on roses in your garden, chances are they’re infected with black spot disease. This disease, scientifically known as Diplocarpon rosae, is a fungus that causes parts of the leaves to develop black spots, eventually yellowing and falling off. So, why get rid of it? Aside from just causing the leaves to decay, it also weakens the rose plant as a whole. Treating black spots on roses as soon as you notice them is key to keeping the rose plant happy and healthy.

Read more
Everything you need to know about permethrin garden spray, what it does, and how it helps your garden
Are there any drawbacks to this popular insecticide? Find out here.
A chrysanthemum plant with several round, reddish-pink flowers

Pests are just a fact of life anywhere there are plants around to feed them. As such, pest control is an ongoing issue for most gardeners, but it can be hard to find a spray that works for you. If you’re new to gardening or just new to the pest control aisle, you may not have heard of permethrin before. If you’re confused about what permethrin is, where it comes from, and what it’s good for, then you’re in the right place. We’re here to clear up questions you have, starting with the basics.

What is permethrin?
Permethrin is a compound of three chemicals based on a similar compound, pyrethrin, found in flowers in the chrysanthemum family. Chrysanthemums produce pyrethrin as a form of natural pesticide. Permethrin is the synthetic form of this natural compound, so there are some slight differences between the ratio of each chemical in the spray versus in individual plants — namely, the ratio in each individual plant can vary, but the ratio used in sprays is consistent so that you always know exactly what you’re getting.

Read more