Do you have small black flies living in your house plant compost? Or hovering around your house plants? These are fungus gnats, also known as house plant flies and sciarid flies. They’re mostly harmless – adult gnats cause little or no harm to plants, but they can become a nuisance in the home. Their tiny worm-like larvae live in the top 5-8cm of compost, where they feed on algae, fungi and plant roots. Healthy house plants usually tolerate this minor root damage, but the larvae can harm seedlings or weak plants.
If you’re a houseplant parent, you’ve likely encountered those tiny, pesky flies hovering around your plants. These annoying insects are known as fungus gnats, and they love laying their eggs in the moist soil of potted plants. Once the eggs hatch, the larvae feed on fungi and organic matter in the soil, which can damage your plants’ roots. Getting an infestation of these small flies under control takes some work, but it’s doable with the right techniques.
Identifying Fungus Gnats
Fungus gnats are very small (about 1/8 inch long) and resemble mosquitoes. They’re attracted to damp soil and decaying plant matter. If you look closely, you’ll notice their dark gray or black bodies and long, spindly legs. The larvae are tiny, about 1/4 inch, and transparent white with black heads. They leave behind traces of slime that look like slug or snail trails. Fungus gnats are especially active in fall when plants get moved indoors.
Where Do They Come From?
Adult fungus gnats lay eggs in moist potting soil, where larvae then emerge to feed on fungi and organic matter. They can fly in through open doors and windows or hatch from eggs laid in bagged soil or new plants. Keep an eye out when buying new plants or soil. Examine them closely for signs of fungus gnats. Quarantine new plants before introducing them to others.
Prevention is Ideal
It’s much easier to prevent fungus gnats than eliminate an infestation. Here are some tips:
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Allow soil to dry out between waterings Fungus gnats need moist soil
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Use sterile, fresh potting mix when repotting plants Avoid opening bags that could be infested.
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Apply sand or small rocks as a top dressing to dry out the soil surface.
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Bottom water plants to keep the topsoil drier.
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Fix any drainage issues and avoid overwatering.
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Quarantine and inspect new plants before introducing them.
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Keep plants away from open doors and windows to avoid flies coming inside.
Ways to Get Rid of Fungus Gnat Infestations
If you already have an infestation, here are some effective remedies:
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Let the soil dry out completely between waterings. This kills eggs and larvae.
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Cover soil with a thin layer of sand or aquarium gravel, which dries out the top layer.
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Use yellow sticky traps near plants to catch adults. Replace traps regularly.
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Mix a solution of hydrogen peroxide and water to kill larvae. Drench soil with it.
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Set out a bowl of apple cider vinegar mixed with dish soap under plastic wrap with small holes. This homemade trap will draw in and drown flies.
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Apply a light layer of cinnamon on top of the soil, which can act as a natural fungicide.
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Remove any dead leaves or debris from the soil surface where flies like to lay eggs.
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Use Bacillus thuringiensis treatments, which contain bacteria deadly to larvae but harmless to plants.
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Repot plants in fresh, sterile soil to fully eliminate larvae in the soil.
Be Vigilant About Checking for Fungus Gnats
Don’t let these small flies take over your lovely houseplants! Carefully inspect any new plants before bringing them home. Monitor plants frequently to spot any signs of infestation right away. Keep soil on the drier side and address drainage problems. Implement preventive measures like quarantines, sterile soil, and bottom watering. If you do get fungus gnats, take rapid action with traps, natural treatments, and soil drenching to get rid of them. With diligence and the right techniques, you can have a fungus gnat-free indoor jungle in no time!
How to identify fungus gnats
Fungus gnats are small black flies that fly around house plants and live in house plant compost. You may mistake them for fruit flies – but if they’re in and around your house plants, they’re likely to be sciarid flies.
Step 1: Water less often[image id=”34362″ size=”landscape_thumbnail” align=”none” title=”Watering the compost” alt=”Watering the compost” classes=””] Watering the compost
Fungus gnat larvae need damp compost to live, as this is where algae and fungi thrive, on which the larvae feed. Simply by allowing the compost dry out between waterings, you’ll greatly reduce the fungus gnat population.
No more black flies ’round your indoor plants – Fungus Gnat Control tips // The Gardenettes
FAQ
How do I get rid of little flies around my houseplants?
Water with a diluted 4:1 hydrogen peroxide solution to kill larvae, as an inch of sand on the surface to prevent adults from laying eggs, and put yellow sticky traps in the plants to catch the flies as they emerge from the soil (larvae pupate in the top inch of soil, then fly out as adults).
Why do my plants have so many little flies?
If you notice flies around your houseplants, it might be a sign of overwatering, as moist conditions favor their breeding. To manage them, allow the soil to dry out between waterings, use sticky traps, or consider using beneficial nematodes or insecticidal soap to control the population.
Will coffee grounds get rid of fungus gnats?
Coffee grind is great at removing gnat infestations. Dry the grind thoroughly – this will prevent mould from forming – and spread it over the potting soil. A thin layer will keep the female gnats from laying their eggs.
How do I get rid of gnats without killing my plants?
Try easy home remedies like hydrogen peroxide, vinegar, and cinnamon—without killing your plants.Jul 30, 2024
Why do bugs fly around my houseplants?
The pesky bugs are attracted to moist soil. Where Do They Come From? If you often see small insects flying around your houseplants, you likely have a fungus gnat issue. The insects are attracted to the moist soil of plants, which provides them with an ideal habitat for raising their young.
What are plant flies?
Plant flies, otherwise known as fungus gnats, are tiny little creatures that settle in plant soil and munch on the roots. They are usually attracted to moist soil that is rich in organic matter. They can be found in houseplants, greenhouses, gardens, and so on.
How to get rid of flies in house plants?
Some easy tips to get rid of the little flies in your house plants are as follows: Get educated about the house plant species you buy to know their proper watering and sunlight needs. Invest in a good quality ventilation system for your home. Check your plants for gnat larva or eggs by stirring the soil with a small stick.
Why are there small flies in my house plant?
This may result in financial loss and a lot of mental stress. The small flies indicate that fungus is growing inside the house plant. Growing fungus releases spores into the air. If a person breathes in these spores, their physical health can get badly affected. The person may suffer from breathing allergies, tremors, nausea, chronic pain, etc.
Are flies destroying your houseplants?
Sharing is caring! One of the worst enemies of houseplants is definitely plant flies, as well as various pests and fungi that cause deadly diseases. You might have noticed small flies around your houseplants around the same size as fruit flies and similar to mosquitoes in appearance.
Are fungus gnats and fruit flies destroying your houseplants?
Unfortunately, our love and admiration for our beautiful houseplants can be spoilt by tiny flies such as fungus gnats and fruit flies. This often leaves us, and your houseplant frustrated. How to get rid of plant flies is easy when you know how with Happy Houseplants blog.