Help - fungus gnats! How to get rid of them (2024)

Prevention and removal tips

Fungus gnats are those small, annoying black flies that terrorise your plants. Where do they come from? And, more importantly,how you get rid of them? The tips below will help you stamp them out and prevent them from returning— hooray!

Before we start with the steps for prevention and removal, it'd be good toknow more about this flying pest. Fungus gnats are most active at the beginning and end of the summer, and they love damp soil. An adult fungus gnat only lives for 1 to 2 days, but females layover 200 eggs in one go. Once a larva reaches adulthood, she immediately lays new eggs in the damp soil of your beloved plant. It’s no surprise that they’re tricky to get rid of, but we're here to give you some tips on how to deal with their presence and stop them coming back.

How to prevent them

#1 Don't overwater
Fungus gnats love damp soil, so not overwatering your plants helps avoidinfestation. It’s no fun laying eggs in dry soil, so the fungus gnats will give your plants a miss!

#2 The right pots
Buy pots with a hole in the bottom, and place them on saucers. That way you'll prevent the damp soil from damaging the roots, as it can cause them to rot.

#3 Keep things clean
Fungus gnats do well in compost-rich soil. Regularly remove dead leaves and twigs from the pots to keep the soil clean, dry and well-ventilated.

How to fightthem

#1 Isolateyour plants
If you find that fungus gnats have invaded one of your plants, place it somewhere separate for 1 to 2 weeks so that other plants are not infected. To be on the safe side, youshould also do this with new plants before you introduce them to the rest of your plants.

#2 Repotting helps
Repotting is an effective way of getting rid of the gnatlarvae. Clean the pot thoroughly and place the plant in new, clean potting soil. The rotting roots, plant remains and damp soil that fungus gnats love so much will be completely gone.

#3 Fancy some wine?
Place a saucer of wine near a plant to attract itsfungus gnats. Funnily enough, fungus gnats find wine much more appealing than soil. They dive right in and... well,you can imagine what happens next.

#4 Sand it down
Scatter a layer of sand on top of the soil in the pot. Tough sandmakes it much harder for the gnats to lay eggs.

#5 Home brew
Boil a litre of water and stir in two tablespoons of cinnamon. Leave to cool and then use it to water your plants—the gnats hate it!

#6Yellow to make them see red
Fix yellow-coloured sticky paper or yellow traps near your plants. The gnats will fly straight towards it, and get stuck! Problem solved.

#7 Sulphur sufferer
You can rid yourself of gnats with matches— but you don't have to set fire to your plant. Instead, stick the matches head downwards in the soil. The sulphur will put them right off.

#8Plants to the rescue
Did you know that carnivorous plants love to eat little black fungus gnats? Place a Sundewnext to the infected plants, and watch it clean up the flies.

Do you have any more tried and tested tips for getting rid of fungus gnats, or any plants that have survived these problematic creatures? Share your story with us on Facebook or Instagram using #thejoyofplants

Help - fungus gnats! How to get rid of them (2024)

FAQs

Help - fungus gnats! How to get rid of them? ›

Eradicate your fungus gnat infestation for good with the following method: Put up a bunch of sticky traps, top-dress the soil with sand and do nematode soaks every 10 to 14 days until the problem is resolved. Also, stop overwatering your plants and eliminate any unnecessary sources of moisture.

How do I get rid of fungus gnats ASAP? ›

Sticky Traps

Flypaper or more modern decorative sticky traps are popular options to catch any fungus gnats buzzing around houseplants and windows. Small yellow sticky traps can be cut and placed on wooden stakes and inserted into pots close to the soil, where adults tend to crawl and fly.

What is the best fungus gnat killer? ›

A peroxide solution apparently kills larvae and eggs on contact, effectively killing off all infant gnats and disrupting the lifecycle. You should be able to buy hydrogen peroxide from any high street pharmacy or online. Mix 1 part 9% hydrogen peroxide with 6 parts water.

Can I spray my plants with vinegar to get rid of gnats? ›

Homemade gnat repellent spray: A mixture of dish soap, water, baking soda, and vinegar can be filled into a spray bottle. The mixture should contain a few drops of dish soap, a tablespoon of vinegar, and baking soda per cup of water. A few sprays of this mixture is an effective gnat repellent.

What is a home made remedy for fungus gnats? ›

Combine 20 drops of tea tree oil with a litre of water. Water the infested plants with this mix, and you should help remove any larvae in the soil. For the adults, use some adhesive traps around the plant.

Can you permanently get rid of fungus gnats? ›

Eradicate your fungus gnat infestation for good with the following method: Put up a bunch of sticky traps, top-dress the soil with sand and do nematode soaks every 10 to 14 days until the problem is resolved. Also, stop overwatering your plants and eliminate any unnecessary sources of moisture. That's it.

Why won t fungus gnats go away? ›

Fungus gnats are persistent and will not go away on their own. These pests lay their eggs and multiply quickly, so infestations will continue to grow. The only way to get rid of fungus gnats is to follow a rigorous cleaning program until the infestation has cleared.

Can I use hydrogen peroxide to get rid of fungus gnats? ›

Additionally, hydrogen peroxide acts as an insecticide, killing the fungus gnats on contact. To get rid of fungus gnats, mix a solution of one part hydrogen peroxide with four parts water. Pour the mixture onto the soil around the infested plant.

How do you make homemade gnat spray? ›

If you just have a couple scouts checking out the accommodations—as in, the gnats aren't swarming yet—fill a spray bottle with a cup of water, a tablespoon of vinegar, and a few drops of liquid dish soap and give it a good shake. Spritz gnats in flight to put an end to the infestation before it begins.

What spray kills gnats but not plants? ›

Mix one part of hydrogen peroxide and four parts of water. Use this solution to water your plants. Hydrogen peroxide will kill the gnat larvae and not injure your plant. Keep reapplying weekly until you notice the gnats are gone.

What kills gnats in plant soil? ›

For hydrogen peroxide, mix one part 3% hydrogen peroxide with four parts water. Carefully pour this solution onto the top of the soil, ensuring it reaches the root zone. The hydrogen peroxide will help kill the gnat larvae and any eggs in the soil without harming your plant.

Is hydrogen peroxide safe for plants? ›

Hydrogen peroxide (H2O2), occurs naturally in rainwater and acts as nature's cleanser. It oxygenates soil and bodies of water, is non-toxic and safe to use around food, people and animals. Adding it when watering your indoor plants, mimics what Mother Nature does for outdoor plants every time it rains.

Does cinnamon get rid of fungus gnats? ›

There is little more annoying than a bevy of gnats in your home. You may get one or two and think they are gone only to find the pesky bugs flying around your face again. However, a little cinnamon can help get rid of gnats that live on your plants by helping reduce fungus.

What is the best gnat killer for indoor plants? ›

Treat Your Soil to Kill Gnats

You can treat your soil by adding diatomaceous earth to every pot. This powder is fairly effective at killing fungus gnats since it dries out and injures the insects. You can add it to fresh soil or sprinkle it on top of the potted soil.

Why do I keep getting fungus gnats? ›

If you develop a fungus gnat problem out of the blue, chances are you're watering too much or have some other issue with dampness in your home, per Colorado State University Extension. Fungus gnats only lay their eggs in damp soil, so if you can correct the dampness issue, they'll happily move out (or, you know, die).

How long does it take for fungus gnats to go away? ›

In cooler weather it can take 4 to 5 weeks or more to complete the life cycle, so winter treatment can take longer. That's why I always recommend treating for 2 months (8 weeks), but at least 4 weeks minimum if you've caught it early and only have a tiny infestation.

Why do I suddenly have fungus gnats? ›

They can also come from bagged potting soil or just consistently damp soil. Adult gnats need warm, moist soil in order to lay eggs and for the fungus gnat larvae to thrive. The first step you want to take to get rid of gnats is to back off on watering and give the soil more time to dry out.

How do you get rid of gnats in plants fast? ›

Make cider and vinegar traps: Similar to how you might trap fruit flies, mix equal parts of cider and vinegar in a shallow dish or can. Place the trap near the affected plant or even on the soil surface inside the container. The pests will be attracted to the mixture but will drown after they land in it.

What kills gnats without killing plants? ›

Food-Grade Diatomaceous Earth

DE, as it's known, is an organic, abrasive powder you can buy to sprinkle over the dry soil in your plants. It will trap the gnats until they die from dehydration.

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