How to Get Rid of Fungus Gnats and Why You Absolutely Should

Photo of author

By Jeff Hale

You may (or may not) know that fungus gnats are the leading cause for your plants not flourishing properly. So they really need to go.

Below, I’m going to show you how you can keep your plants from getting fungus gnats either by killing them with some SUPERB organic products or preventing them naturally.

Let’s get into it.


How to Get Rid of Fungus Gnats in 3 Steps

The below steps are considered natural and the most recommend ways to discourage these little critters.
how to get rid of fungus gnats

Step 1 – Let your soil dry

By letting the soil dry out before your next watering, the gnats will be discouraged from laying new eggs (gnats love moisture).

Step 2 – Spray your soil

Spray the soil with a mix of water (1 cup) and add a few drops of dish soap or Castille soap. Make sure to repeat this step after a few days.

Step 3 – Add sand or gravel into your soil

Fungus gnats larvae are only found in the top inch of soil. By replacing the top inch with sand or gravel, the gnats will be discouraged from laying more eggs because of the dry environment.

Organic Products That Kill Fungus Gnats and Larvae

Below is a list of recommended organic products that will also kill fungus gnats quickly, some are faster than others. But all tried and tested.

Hydrogen Peroxide

  • Easily accessible and lives on the shelves of many homes.
  • Use as a soil drench solution
  • Kills fungus gnat larvae instantly
  • Doesn’t harm your plant
  • Inexpensive

Mosquito Bits

  • Works by killing gnat larvae with natural bacteria
  • Environmentally friendly
  • User friendly
  • Can be used by sprinkling them into the topsoil or incorporating them into the soil before planting
  • Safe for plants

Neem Oil

  • You may use it as a soil drench to kill fungus gnat larvae
  • Use as a topical spray mixed with water
  • Regular use can keep them from reproducing
  • User friendly
  • Safe for plants


  • Can be used for indoor plants, professional greenhouses, and gardens
  • Made with food-grade formulation ingredients
  • Contains organic ingredients like Azadirachtin A & B
  • Safe for plants
  • Environmentally safe

How To Prevent Fungus Gnats

Avoid overwatering your plants. Fungus gnats thrive in moist environments. If you see them or the larvae, avoid watering until the soil has dried up.

They are common in nurseries and green gardens, so carefully inspect your plant before buying it.

  1. Check the base of the plant, gently looking through the soil to find signs of the gnats or the whitish fungus gnat larvae
  2. Be sure that new plants are pest-free by quarantined them from other plants for at least 2-3 weeks
  3. During the quiet, regularly check for any sign of infestation
  4. If the infestation is present, follow the proper steps before bringing the plant into your home
  5. Mulching can help against fungus gnat infestation because of its dry temperature

What Are Fungus Gnats?

Six different families make up the fungus gnats species. These six families include the Mycetophilidae, Diadocidiidae, Ditomyiidae, Bolitophilidae, Keroplatidae, and most importantly, the Sciaridae.
what are fungus gnats

Most fungus gnat species are not harmful to plants, except for the Sciaridae family. We dive deeper into the Sciaridae later in the article. So keep reading!

They are quite the little troopers and produce eggs at an astonishing rate, which quickly become deadly to your plants.

Fungus gnats are an invasive species. They form when laying their eggs in the soil near plant roots. Their larvae will feed off the plant root and fungi in the soil until they’re ready to hatch.

Usually, this process takes place at the plant nursery. So, by the time you bring a new plant into your home, the fungus gnats have fully hatched. They’re ready to begin a new cycle by hatching eggs of their own.

Did You Know? Some plants can increase oxygen production in your home. This can help with respiratory problems caused by asthma, anxiety, or COPD.

What Do Fungus Gnats Look Like?

It’s important to know what these pests look like to identify them and treat them! They can be hard to spot because of their similarity to fruit flies. They are small and dark-looking insects that live in the soil of houseplants.
what do fungus gnats look like

Fully developed fungus gnats can also be mistaken for mosquitos because of their similar shape. However, they are much smaller than most mosquitos and flies.

The best way to know if you have them is by watering your plants or disturbing the soil. They will come to the surface almost immediately.

It would help if you also were on the lookout for the fungus gnat larvae. They have a shiny black head with an almost clear body. They can reach almost a quarter inch in length, which makes them hard to find, especially since they live in your plants’ soil.

When in doubt, begin a mild treatment on your plants. You can use hydrogen peroxide as a safe and fast treatment. Don’t worry. Down below I’ve provided some step-by-step instructions for how to treat fungus gnats!

Quick Pro Tip: Regularly check the soil moisture for soil and plant health. Checking moisture levels is best done with a soil moisture gauge by inserting it into the soil. This special gauge can tell you if the soil is dry, moist, or wet.

What Is The Life Cycle of A Fungus Gnat?

Fungus Gnats live a fast and short life. Their life-cycle consists of four different stages (egg, larvae, pupae, and adult). They can live for about a week as adults, so they lay about three hundred eggs in that week.

Once the egg is all laid in, the small-sized larvae will form shortly. During the growing process of the fungus gnat larvae, their size increases at a tremendous. The fungus gnat larvae grow so fast by eating organic matter in the soil.

After the larvae are fully grown, they will form into their pupal phase. The pupae will live under the soil’s surface until they are fully formed, adults.[/note]

Quick Pro Tip: Overwatered plants are more susceptible to hosting gnats and others pests. Most plants only need monthly watering (check your specific plant type for more information).

When are Fungus Gnats Most Active?

During the fall is when they become more active in the home. Not because gnats prefer cold weather, but quite the opposite, actually. To elaborate, this happens because of the cool weather that drives the gnats to find warmer temperatures inside.

Making your home or greenhouse a primary target for these pests. So start taking the necessary precautions in the hot summer months.

Many plant parents bring their outdoor plants inside in the fall. This causes their population to overlaps one another. This happens when the adult gnats from the summer reproduce again in the warm weather inside your home.

Do I Have Fungus Gnats?

As I mentioned earlier, a great way to know if you have fungus gnats is disturbing the soil. This can happen by watering your plant and moving the soil around. Adult flies buzzing around your garden can also be a sign.

You should also regularly monitor your plants for any yellow leaves or slow growth. If fungus gnats are present, treat all your plants immediately, regardless if they are having symptoms or not.

Sadly, you recovering plants can still be at risk for fungal diseases. Fungus gnat larvae spread fungus spores, which can be the leading cause of many common plant diseases. So taking the necessary steps and using the right tools is key to healthy plant life!

Effects of Fungus Gnats

Most fungus gnat species are not harmful unless it’s in the Sciaridae family. Be aware of the fungus gnat larvae in this family, as they are the most harmful during this stage. The fungus gnat larvae can chew through the roots and spread disease.

They do this by picking up the spores from infected plants or soil, which causes your plants to develop scabs, leaf spots, and cankers, which causes the leaves to turn yellow and wilted, eventually causing plant death if not treated properly.

Quick Pro Tip: Provide drainage holes for your indoor plants. Plants not being able to drain properly is the main cause of rotting and root problems.