Fungus Gnats - 4 Effective Ways to Get Rid of Gnats in Plants (2024)

What are fungus gnats?

Fungus gnats (Sciaridae) are small pests that feed on houseplants. They belong to the Diptera group of insects. Some mistake them for fruit flies, although they have nothing to do with each other. They appear especially if the plants are weakened. Quick multiply rate is characteristic for them. Thanks to this, they can spread quickly across the entire household. Adult gnats fly from pot to pot, to lay their eggs.

What do fungus gnats look like?

Fungus gnats have different forms – depending on their development stage. At first, they are small, white larvae with dark heads – they can be noticed in houseplants’ soil. They are no longer than 6-7 mm. They can be even smaller. As they grow up, they turn into small, black insects. They are even tinier – usually no longer than 4-5 mm.

Where do fungus gnats come from?

Fungus gnats typically appear wherever they can find perfect conditions to multiply. They can be often spotted in pots with undernourished, overwatered plants. The small insects particularly enjoy peat-rich soils. Plants that grow in warmth or sunny spots are also likely to get attacked by these pests.

Are fungus gnats dangerous to plants?

Although adult insects might be irritating to the household, they don’t pose a threat to plants. But their larvae can be dangerous. Their presence in a container might lead to various fungal diseases. The creatures also tend to bite plant roots and stems. A lot of fungus gnat larvae might cause the plant to wither and even die.

Are fungus gnats difficult to get rid of?

Although fungus gnats are bothersome and quickly spreading insects, they are not as difficult to get rid of as it might seem. Regarding plants that can easily survive droughts e.g., palms, cacti, agave, aloe, just stop watering them for some time. This way, the larvae will die naturally.

What about other plants? Spraying the soil with a special mixture is a good solution. Prepare it by crushing a few garlic cloves and pouring hot water over them – 500 ml is enough. Spraying the plant regularly for 4-5 days should work. It’s a perfect, natural way to get rid of gnats in plants.

There are a few other methods to fight fungus gnats. Just pick the one perfect for you.

Fighting fungus gnats with cinnamon – a proven method

Fungus gnats hate the sole smell of cinnamon. It means you don’t even have to use the spice. Cinnamon essential oil should work – its aroma will repel the pesky insects. But such a remedy cannot be used in high concentration. Add 15 ml of cinnamon oil to a glass of water. Use the solution to spray the fungus gnats.

If you don’t have the oil, you can, of course, use regular cinnamon. Just sprinkle the soil with the spice.

Cinnamon works only against adult fungus gnats – it repels them. This method only prevents the insects from spreading onto other houseplants. To eliminate the larvae, you need other methods.

Baking soda for fungus gnats

Baking soda is used against fungus gnats exactly like cinnamon. It means you can either prepare a spray or sprinkle it directly in the pot. It might have a weaker effect than cinnamon, but it should work if the gnats aren’t numerous.

Baking soda is beneficial for plants, as it prevents many diseases. For instance, it works perfectly against botrytis.

How to get rid of fungus gnats? Use garlic powder

Garlic is great as a repellent of adult insects, as well as larvae. Fresh garlic turned into a brew is the best option, in this case. But if you don’t have it at home, you can also use garlic powder.

• You can prepare an extract by pouring hot water over garlic powder. Use the strained liquid as a spray. 3-4 tablespoons of the spice per 300 ml of boiling water are enough.
• Another possibility is much easier – just sprinkle some garlic powder in the pot.

Be careful if using this method in sensitive plants. The first solution should be safe, but avoid pouring garlic powder directly into the pot, in this case.

Sticky traps for fungus gnats

If you aren’t a fan of the smell of garlic or cinnamon, or you don’t have baking soda at home, special sticky traps might be a good solution. You can purchase such products in any gardening store. Many people also purchase them online.

Sticky traps designed for fungus gnats are yellow – and not without a reason. This color attracts the insects. As they land on the trap’s surface, they get immobilized.

Sticky traps are very safe, as the product doesn’t contain any dangerous chemicals. You can use it if there are children or curious pets in the house.

What are other fungus gnats killers?

Are you wondering whether there are any other ways to get rid of fungus gnats? Of course there are. You can use a chemical fungus gnats killer. Such products are available in many forms. Special liquids designed to be mixed with water and sprayed onto the plant are a popular option. A spray in a can is much more convenient. You can use it to spray the plant and soil in the pot.

Special sticks against fungus gnats in soil are yet another solution. They are highly effective and commonly used – not only they remove the pests, but also fertilize plants.