How to get rid of fungus gnats
3 minute read

This is how to get rid of Fungus Gnats in your houseplants!

Do you spot little, black flies flying around your plant and its soil? Then your plant might be suffering from fungus gnats: a nasty plant plague! Luckily for us, fungus gnats are often considered to be a minor houseplant pest and are easy to defeat. Especially if you start early. Fungus gnats can quickly become a large infestation when you don’t take action right away. So, if your plants are troubled by these small, flying predators it’s time to come into action!

What are Fungus Gnats?

Fungus gnats look a bit like fruit flies, however they are not actually flies. They belong to the big family of mosquitoes. They are also called sciarid flies and are tiny black insects that fly around the leaves and soil of your plant(s). You usually don't notice them until you water the plant or tap the pot: then they suddenly appear. Although the animals seem quite harmless to humans, it may be that they have their sights set on your plant.

You recognise a fungus gnat only when the larva has developed into a fly, but they start as eggs. After the egg phase comes the larvae phase. A larva of a fungus gnat has a long, white or transparent body with a black head. After about two weeks the larvae will develop into adult fungus gnats. So it may be that you only find out after two weeks that you have a fungus gnats infestation! Luckily, there are some great ways to fight this infestation and make your plants happy and healthy again!

How to get rid of fungus gnats

How do Fungus Gnats damage my plants?

When the infestation is small, fungus gnats are more of an annoying sight than anything more. Unfortunately, if the population of fungus gnats get out of hand, the pest can really do some damage to your plants. The larvae will start feeding on plant roots. Especially the young plants and cuttings are often not strong enough yet to survive such an infestation. Because their small roots are affected, they can no longer absorb water and nutrients.

When the roots of a plant are affected, the health and resistance of the plant will also deteriorate. It causes the plant to weaken what makes it more resistant to diseases and fungi. The lower leaves of your plants will turn yellow, it can drop leaves and/or it will grow slower or stop growing. In the end, your plant can also die from this infestation. That’s clearly not what we want, so let’s beat these little predators!

Fungus gnats on sticky fly catcher

How to get rid of Fungus Gnats

Have you found fungus gnats in your houseplant? No reason to panic (yet)! Your green friend will not die immediately. However, the roots can be affected and the chance of diseases and fungi is greater.

If one of your plants is infected, there is a good chance that the fungus gnats will also infect your other plants. Therefore put the infected plant separate from your other plants, preferably in a separate room. Now it’s time to start treating your plant!

Biological pest control

One of our favourite ways to treat plant plagues is with biological pest control. It literally means that you introduce the natural enemy to your plants and they will then go to work to save your beloved plants.

We call the little rescuers that save your plants from fungus gnats ‘Felti’. Felti are microscopically small nematodes that occur in the soil in nature and they are the natural enemy of the fungus gnat. These tiny fighters penetrate the larvae of the fungus gnats and then excrete a bacterium that kills the larvae within 1-3 days. The great thing is that they do not affect the plants in any way! Also, it’s super easy to use. Just add the bag of ‘Felti’ to a watering can with lukewarm and clean water and pour it directly on the plants.

We understand that this is exciting and that you want to know all the ins and outs about how our biological pest control works, especially before you actually release these little creatures on your plants. That's why we wrote a blog about biological pest control.

Let your plant dry out

Because fungus gnats love moist soil, it is important never to overwater your plants. Always choose a pot with a hole at the bottom, so excess water can drain away and the roots of your plant won't rot. Have you already spotted fungus gnats near your plant? Then don't water the infected plant for a while and let the soil dry out. The fungus gnat will then look for another place to lay her eggs. Moreover, the larvae cannot move well in dry soil, so they die out. We also recommend that you renew the potting soil of your plant. Clean the roots and the pot well and spoil your plant with fresh potting soil.

Sprinkle sand over the potting soil

Sprinkle some white sand (like sandbox sand) on top of the potting soil. Fungus gnats cannot lay eggs in this. In addition, the white sand does not contain any nutrients, so the larvae cannot grow either. Do this with all your plants. Make sure you remove the white sand again.

When you no longer have trouble with fungus gnats, otherwise not only the fungus gnats but also your plants will die.

We hope this short blog has given you some useful tips on how to get rid of fungus gnats. Of course, preventing your plant from fungus gnats is better than to cure it, so here we share some tips on how to prevent fungus gnats and some homemade hacks to treat it!


I PLNTS fanno subito la felicità di Renée, che è sempre a caccia di tendenze per le piante. Ispirare la nostra comunità con consigli per gli interni, sorprendenti fai-da-te e divertenti elenchi è ciò che le riesce meglio!

06 agosto 2023