Skip to main content

Fungus Gnats - What Are They? and How to Get Rid of Them!

Year's of professional landscaping knowledge. Experience with irrigation systems, landscape design, pest control, weed control, gardening, +

The Fungus Gnat also Known as Fruit Flies - These tiny pests can reek havoc in your indoor grow space. (image at 1000x magnification)

The Fungus Gnat also Known as Fruit Flies - These tiny pests can reek havoc in your indoor grow space. (image at 1000x magnification)

Fungus Gnats - What Are They? And How To Get Rid of Them!

The fungus Gnat is a tiny flying insect that lives and breeds in moist soil. They feed off of fungus and other organic compounds, such as rotting, or decaying plant matter. They breed very quickly and a single gnat can have up to three hundred larvae.

The Fungus Gnat is an important part of our ecosystem. They serve as a food source for many creatures large and small. Bats, Birds, and even other Bugs eat Fungus Gnats. Like bees, they also can carry pollen from flower to flower. So they are also an important part of human life too.

Unfortunately, Fungus Gnats often feel more like foes than friends to us. They can quickly infest potted plants and interior grow spaces. Such as growing tents or greenhouses. While fungus gnats primarily feed on dying or decaying plant matter their larva enjoy chewing on roots. This can cause serious problems for your plants making them sick or even killing them.

Fungus Gnat Prevention For Indoor Gardening:

Sand, and Small Pebbles

Fungus Gnats love moist areas. They require it to reproduce. Thus, the gnats seek out moist or wet areas. Using sand, or pebbles can help create the illusion that your media is dry and unstable for procreation. Increasing the chance that the pest will leave your plants alone.

Using Perlite For Indoor Garding

What is Perlite? Perlite is a compound made from glass. Imagine being able to pop glass-like popcorn. Turning it into white, light, and fluffy pieces. That's exactly what Perlite is. Volcanic glass expanded by extreme heat and popped into small white fluffy balls that look like pearls or broken bits of popcorn. Always be sure to wear a mask when using Perlite because the fine dust it produces can be harmful if inhaled.

The use of Perlite can help your indoor garden in many ways. Mixing Perlite into your potting medium can help the overall drainage and irrigation. It helps to prevent overwatering and root rot. Which in turn will help prevent fungus gnat infestations. Also covering the top of your potting medium with Perlite can help disguise your moist soil. Making it look dry and unsuitable for living conditions.

Avoid Over Watering

You mustn't overwater your plants. Overwatering will cause root rot and will attract fungus gnats. The use of a soil moisture meter can help regulate watering and prevent overwatering.

Integrated Pest Management (IPM) and Non-systemic Preventatives

Integrated Pest Management (IPM) takes a non-abrasive and environmentally safe approach to solving pests problems. These methods rely on common sense and pest research. This, combined with natural pesticides offers a safe and non-hazardous way to control pests. These methods can be applied both in the home garden and in agriculture.

Knowing your pest is the key to defeating them. Research information about your pest. The first place to start would be to identify your pest! Next, ask the following questions:

  • What is its lifespan?
  • What does it like to eat?
  • What kind of environment does it thrive in?

These types of questions and answers can help point you in the right direction for controlling your pest.

Scroll to Continue

Non-systemic Preventatives for Fungus Gnats

The Use of Soap in The Garden

Using soap as a pesticide can be very effective against many pests. It is simple to make a soapy solution that will kill gnats and not hurt your plants. Best of all it only requires a few inexpensive items:

  • A spray bottle
  • Dawn dish soap
  • Water

Here's how it works. Simply mix a few drops of dawn dish soap into a spray bottle of water. Shake it up, and "voila"(wallah). You now have a bottle of bug-killing fluid. When sprayed on small flying insects like gnats, they easily get stuck in the soapy solution and drown.

Neem Oil

Neem oil is a type of vegetable oil. It is extracted from the fruit and seeds of the Neem Tree. Neem oil is a natural pesticide against many insects including the Fungus Gnat.

How To Use Neem Oil In Your Garden

Simply mix 20ml of Neem oil into a one-gallon bottle of water. Shake well. Pour the solution into a clean spray bottle and apply it directly to your plants. Also if your plant is potted spray the top of your potting media. Gnats not only hate the smell of Neem oil, but it is also toxic to them. With regular use, your plants will quickly become an inhospitable environment for the pests.

Gnat Traps

Sticky Yellow Houseplant Traps - These traps are exactly what they sound like. They are covered with an extremely sticky adhesive and are colored bright yellow. Insects including Gnats are attracted to the yellow color. They fly or crawl onto the trap getting stuck and eventually dying.

Apple Cider Vinegar and Dawn Soap -
Gnats love the smell of apple cider vinegar and will be attracted to it. You can take advantage of this knowledge by setting a cider trap. Here's how it works. Simply pour some apple cider vinegar into a jar. Add a few drops of dawn dish soap. Next mix the solution. Then use some plastic wrap to cover the top of the jar. Now poke some holes in the plastic wrap with a pen or pencil. Place the jar in an area where you notice the pests. The bugs will enter the jar and drown in the solution.

Red Cup of Death - Fill a red plastic party cup halfway with water. Add in a few pumps of foaming hand wash or dish soap. Stir gently and place by a windowsill or directly next to the effect potted plant. Shortly after you will notice dead gnats in the soapy solution. I usually notice dead gnats within an hour. If you're not having success try moving the cup to another location.

fungus-gnats-what-are-they-and-how-to-get-rid-of-them
Red Cup of Death. Photo by Jason Nicolosi

Red Cup of Death. Photo by Jason Nicolosi

Final Thoughs

All of these remedies are eco-friendly and are natural ways to control pests. I hope they help you control your pest problems and keep your environment safe. Happy gardening!

This content is accurate and true to the best of the author’s knowledge and is not meant to substitute for formal and individualized advice from a qualified professional.

© 2022 Jason Nicolosi

Related Articles