How to Get Rid of Gnats in Plants

If you notice small flying insects around your houseplants, they are probably fungus gnats. Don’t worry, removing and preventing fungus gnats on plants is very easy. Normally, you will observe even more of these gnats in plants after watering the plants. Learn how to get rid of gnats in plants.

Of course, in this article you will also learn how to prevent gnats on plants, so you will never have to deal with these irritating flying insects again. Many people confuse fungus gnats with fruit flies, but they are different, and we will see the differences between the two in this article.

What Are Fungus Gnats?

What Are Fungus Gnats? Fungus gnats are very small flying insects that have physical similarities to the common mosquito. They have slender, gray bodies like the common mosquito and are between 1/16″ and 1/8″ long, and have long, slender legs. A female fungus gnat can lay up to 200 eggs that will later develop into a larva, pupa, and finally into an adult fungus gnat.

When the eggs of the fungus gnat hatch, they will develop into tiny larvae that will feed on the fungi produced in the damp soil (hence the name fungus gnats). That is why you will easily observe many fungus gnats because they reproduce quickly and will always be near the pot where they were born. The life cycle of these insects is approximately 3 weeks.

Some people when they see insects flying around their plants think they are fruit flies, but they are different. Fruit flies are very similar to common flies, but slightly smaller and, compared to fungus gnats, have shorter legs and larger heads. Here is an image so that you can see the differences between the fungus gnat and the fruit fly.

what are fungus gnats
In the pictures, you can see the differences between the fruit fly and the gnats in plants.

What Causes Gnats in Plants?

What Causes Gnats in Plants? There can be several causes of gnats in plants, such as lighting and organic debris, but the main cause of gnats in plants is excess humidity. Heat and humidity are the optimal conditions for fungus gnats to develop. Overwatering is one of the first causes of fungus gnats. Rising temperatures and heat also help their proliferation.

Also, the fungus gnats are attracted by the organic debris in the pots, because this is the food for the gnat larvae. Apart from being attracted to organic debris and moisture, they also like light, and that is why you can see the fungus gnats flying around light bulbs.

what cause gnats in plants
What Causes Gnats in Plants? Normally, excess moisture in the soil is the main cause of gnats appearing in plants.

How to Get Rid of Gnats in Plants Naturally

How to Get Rid of Gnats in Plants Naturally? There are several ways to get rid of gnats in plants naturally. Any of these ways are valid to eliminate the gnats in plants, just choose the one that is easiest for you.

Make sure to eliminate all the gnats with these methods, so you will never have them bothering your plants again. Continue reading to see all the natural ways to get rid of fungus gnats.

Let the Soil Dry

As mentioned above, the fungus gnats and their larvae love moisture, which is why you will let your plant water for a few days to let the soil dry out. As the soil dries out it will kill the larvae and their eggs, don’t worry your plant will survive a few days without being watered.

Bury a stick in the soil and check to see if the soil is moist, only the first few inches (cm) of soil need to dry out. It is very important to have a well-drained substrate and that the pot has good drainage holes.

Add Diatomaceous Earth to the Pots

Diatomaceous earth is a good natural and organic way to get rid of gnats in plants. Diatoms are fossilized unicellular algae with a silica coating. This coating, upon contact with the insect, perforates its keratin layer, causing its death by dehydration.

Spread a little diatomaceous earth on the surface of the soil, and that will be enough to get rid of the gnats and their larvae. Diatomaceous earth provides micronutrients such as phosphorus, nitrogen, and potassium to the soil. Learn more about how to use diatomaceous earth in potted plants.

diatomaceous earth get rid of gnats in plants
Diatomaceous earth is an excellent way to get rid of gnats in plants.

Bottom Watering Your Plants

Bottom watering plants is very simple. You only need to have a dish deep enough to hold the water and that also fits the submerged part of the pot.

This form of irrigation prevents the upper part of the substrate from getting wet so that only the bottom of the soil is moistened and absorbed by the roots.

Use Sticky Fly Traps

Sticky fly traps are a good way to get rid of gnats in plants. This way you can trap the adult gnats and without adults, they will not reproduce. I recommend yellow sticky fly traps; the yellow color attracts more gnats.

You could combine sticky fly traps to catch the adult gnats and then spread some diatomaceous earth to remove the larvae from the soil.

sitcky fly traps for gnats
Sticky fly traps allow you to get rid of gnats in plants and other insects.

Sprinkle Cinnamon in the Soil

Cinnamon in plants is very good because it is a natural fungicide. An advantage of cinnamon is that it is always available at home or can be easily bought in any store, and it is inexpensive.

Sprinkle a little cinnamon on the surface of the soil, in the same way, you would sprinkle diatomaceous earth. This will eliminate the fungus and also the gnat larvae that feed on the fungus.

Automatic Indoor Insect Trap

There are many automatic traps for indoor insects, most of them have a UV light that attracts the insects such as the gnat and then a fan sucks it out. After being sucked in, the insect is trapped inside a sticker.

It is very similar to sticky fly traps, but without the need to put the traps everywhere in the house. It is also very quiet and works for a wide variety of insects, I must admit I have one at home, but I use it for common mosquitos.

automatic indoor insect trap
The automatic indoor insect trap is excellent for eliminating gnats from plants. In the image, you can see the number of gnats that it trapped.
Katchy Indoor Insect Trap - Catcher & Killer for Mosquitos, Gnats, Moths, Fruit Flies - Non-Zapper Traps for Inside Your Home - Catch Insects Indoors with Suction, Bug Light & Sticky Glue (Black)
  • Triple trapping power: a UV light, powerful fan, and sticky glue board combines to be an effective way for how to get rid of fruit flies, gnats, and other small bugs. Simply turn on/off when needed.
  • Use the fruit fly trap for indoors close to insect-ridden fruit, plants or trash bin. Turn off the lights for best results.
  • No more ugly traps! Subtle and stylish; easily place in your home, kitchen, or office as a decorative piece. No zapper needed.

Water With Mosquito Dunks

Mosquito Dunks is a product containing a bacterium called Bacillus thuringiensis israelensis, also known as BTI, which naturally eliminates gnat larvae without affecting plants or other animals.

Just add the product to the water in your watering can and water the plants. It will kill gnat larvae for up to 30 days. A scientific study found that using the bacterium Bacillus thuringiensis israelensis in the substrate had positive results against gnat larvae.  This is a very effective and environmentally friendly way to get rid of gnats in plants.

Summit...responsible solutions 110-12 Mosquito Dunks, 6-Pack, Natural
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Summit...responsible solutions 110-12 Mosquito Dunks, 6-Pack, Natural
  • Kills mosquitoes before they're old enough to bite
  • The only product with bti, bacteria toxic only to mosquito larvae
  • Lasts for 30 days and treats 100 square feet of surface water

Hydrogen Peroxide Mix

Dilute 3% hydrogen peroxide in 4 parts of water and water your plant. Mixing in this ratio will eliminate all gnat larvae and also aerate the soil. The important thing is to use hydrogen peroxide at 3% and not in higher concentrations because it could damage the roots of the plant. This is also a good way to get rid of the gnats on the plant, we all have hydrogen peroxide at home.

Neem Oil Mix

Neem oil is another natural and organic product used to eliminate different pests. You should use neem oil to get rid of gnats from plants. We recommend our article about how to mix neem oil for plants so that you can prepare it correctly.

neem oil mix gnats
Neem oil with the leaves and fruits of the plant.

How to Prevent Gnats in Plants

How to Prevent Gnats in Plants? Now you know many ways to get rid of gnats in plants. But it is also important to know how to prevent gnats in plants. There are several ways to prevent gnats from invading houseplants, and they are as follows.

The main thing is to avoid excessive watering, if the soil is too wet the gnats will probably lay their eggs. Remember that fungus gnats like humidity and warmth. If the soil is too wet, fungi will grow and feed the gnats’ larvae.

Use a well-drained substrate, and also make sure that the pot has enough drainage holes for proper drainage. Good drainage will prevent gnats from finding moist soil in which to lay their eggs.

It is very important to check the plants if you bring them from somewhere else (for example a store) they may be carrying gnats. Check the plant before bringing it into your home, and if possible, keep it away from the rest of your plants for a few days to prevent gnats.

With these simple tips, you will be able to prevent gnats in plants. We hope this article on how to get rid of gnats in plants will be helpful.

how to prevent gnats in plants
How to Prevent Gnats in Plants? The most important thing to prevent the appearance of gnats in the plants is not to have soil with an excess of humidity.
About Henry Morgan

We are the Morgans, Henry, and Julia, both agronomists from the University of Michigan, where we met. We are experts in putting our hands in the soil and developing organic foods and improving production processes for decades. Likewise, we have worked for companies such as Mondelez International, BASF, Monsanto, etc. currently in our role as science writers for as well as advisors in promoting large scale food growing in urbanized areas. In this website, we share what we are most passionate about, gardening and farming. Enjoy and see real photos on our website.