How to Get Rid of Fungus Gnats in Houseplants Effectively

get rid of fungus gnats

We have tried various methods to remove fungus gnats from our home. Here are the results:

Have you also encountered small black flies in your home that seem to appear out of nowhere and you can't get rid of them? These little flies in house plants are called fungus gnats, and although they are not dangerous, they can be very persistent and annoying, especially when they fly near your face.

Fungus gnats live in houseplant soil during their larval stage. Once the soil containing the fungus gnats reaches your home, they quickly multiply into all the plant pots in your household by laying eggs, which is the main cause of their seemingly endless numbers. In their natural outdoor environment, they have plenty of predators to keep their numbers in check, but indoors, we have to deal with the problem of how to get rid of fungus gnats in plants ourselves.

What are fungus gnats?gnats in house

Fungus gnats are small flies (belonging to several families including Sciaridae, Diadocidiidae or Mycetophilidae) growing to about 1/10 inch (3 mm) in length with a dark body and translucent wings. Their larvae thrive in moist soil rich in organic nutrients and microscopic fungi on which they feed. These miniature larvae are not visible to the naked eye, but once they transform into adult flies, they can be very annoying, especially when flying indoors.

The life cycle of fungus gnats

The adult fungus gnat lives for a maximum of 7 days in the form of a fly, during which time it lays eggs in the soil. The larvae that hatch from these eggs develop in the soil for about 3 weeks and then turn into adult flies.

These small black flies on indoor plants are very unpleasant at the midge stage, but they do not bite or otherwise harm humans. The larvae feed on the organic components of the potting soil and the fungi that decompose them (hence the name "fungus gnats") as well as on the smallest hairs of plant roots. In most cases, the gnats cannot threaten the adult plant, but when they multiply, they can cause root rot and deterioration of the plant's health. This is especially true for small seedlings and plants. In addition, these small flies can also transmit various diseases to other houseplants in the home. 

People often confuse fungus gnats with fruit flies, but unlike gnats, fruit flies feed mainly on ripening fruit.

How to get rid of fungus gnats

To permanently get rid of fungus gnats from your home, you have to do so in all indoor plant pots, and you have to be patient, because fungus gnats have a cycle of up to 4 weeks from egg laying via larval development to adulthood, so whatever product you use, its effect must last at least 1 month. In my experience, not all products against fungus gnats are effective enough to completely eliminate the problem. Therefore, we have divided the ways to get rid of the fungus gnats into three categories according to their effectiveness:

1. Methods for the complete removal of fungus gnats

A proven way to completely get rid of fungus gnats indoors is with insecticides. Of the many insecticides, we will mention 2 biodegradable types safe for indoor use:  

a) Organic insecticides containing pyrethrin - Pyrethrins are organic insecticides that occur naturally in chrysanthemum plants and are effective against several insect species, including fungus gnats. To be effective, the insecticide must be applied at the prescribed rate to the soil in all pots in the home at three-day intervals for three weeks. This fungus gnat killer is quick and safe. Pyrethrin is harmless to mammals and other animals except insects, it is biodegradable and breaks down after contact with air so it is considered safe, even for use on edible plants.

b) Insecticides that contain the bacterium bacillus thuringiensis subsp. Isralensis, which produces toxins specifically for killing insects in the larval stage. This product should also be applied in liquid form several times over a minimum of three weeks.

2. Methods to control fungus gnats

a) Sticky insect traps - A relatively effective method to significantly reduce the population of fungus gnats in the home is to use yellow sticky insect traps placed near pots, to which adult gnats stick before they can lay their eggs. The sticky traps cannot eradicate the fungus gnats completely, but they can be kept under control in this way. 

b) Reduced watering – Fungus gnats thrive in moist soil, so infestation by these insects can be a sign of overwatering. However, if the top inch (3 cm) of potting soil is allowed to dry out completely between waterings, the fungus gnat population can be greatly reduced. The disadvantage of this method is that not all houseplants can be watered at the same time, as some species require more frequent watering than others.

c) Parasitic nematodes - We can also intervene biologically against fungus gnats and other harmful insects living in the potting soil. In particular, parasitic nematodes (Steinernema feltiae), which attack and kill the gnats larvae, are used for this purpose. Application of this natural fungus gnat killer is mainly used on larger areas, greenhouses and edible plants. Parasitic nematodes are now readily available, and their application is very simple.

d) Predator mites – For mite species (Hypoaspis aculeifer, Hypoaspis miles and others), the larvae of fungus gnats are food, so by applying them to the houseplant potting soil, it is possible to reduce the population of fungus gnats in the home

3. Anti-fungus gnat products that didn't work for us

Diatomaceous earth

Cinnamon and cinnamon powder

Coffee grounds

Soap spray

Essential oils (cinnamon, green tea, peppermint, neem)

Vinegarsoap traps


Do you have any tips for getting rid of fungus gnats? Feel free to share them with us in the forum.


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Have you also encountered small black flies in your home that seem to appear out of nowhere and you can't get rid of them? These little flies in house plants are called fungus gnats, and although they are not dangerous,…