What Causes Gnats and How to Get Rid of Them
What Are Gnats?
Gnats are small black or dark-brown insects with long, slender bodies (1/4 inch long) and thin wings. They look like tiny flies, but what you see are full-grown adult gnats. They belong to the Mycetophilidae, Anisopodidae, and Sciaridae families and are weak fliers. There are two types of gnats: non-biting and biting, but the ones you find in your house and yard are typically the non-biting type. The most common types of gnats people find in their homes are fungus gnats, fruit flies, or drain flies (phorid flies).
What Are Gnats Attracted to?
Gnats are attracted to moisture and/or organic material, which is why you'll notice more gnats during the summer than you will during winter. They typically enter the house in search of food and a place to procreate, and gravitate towards decaying organic material, such as decaying leaves or rotten fruit and moist areas inside the home, such as wet potting soil or wet sinks and drains.
The following are causes of gnats inside your house:
- Moisture: Moist breeding grounds for gnats include food spillage, moist potting soil, overwatered grass or plants, garbage cans, puddles in kitchen or outside your house, leaky pipes under the sink, and condensation around windows and vents.
- Fruits and vegetables: Fruit flies appear when you leave produce out in the open, especially sweet-smelling fruits. They are also attracted to fallen or rotten fruits in your garden.
- Decaying organic material: Fungus gnats love rotting plants and flowers. Things they feed on include fungus, mold, moss, and compost. They typically live in your potting soil where they can feed on either root rot or decaying leaves.
- Humans: Perspiration, body heat, mucus from your nose, tears from your eyes, and carbon dioxide are all elements of attraction to the common household gnat. They also like sweet-smelling lotions, perfumes, hairsprays, and detergents, so avoid fruit fragrances if you have a gnat problem.
- Light: Like flies, gnats can't fly very well in the dark, so they swarm around light fixtures and lamps.
Types of Common Household Gnats
Where Is It Found?
What Is It Attracted To?
How to Get Rid of Them
Small and black
Around potted indoor plants
Fungus and mold in potting liner and decaying leaves
Clean up dead leaves/flowers, and allow the soil to dry between waterings. Replace soil and pot liner if there is mold/fungus.
Small and light brown with red eyes
In the kitchen
Ripe or rotten fruits and vegetables
Remove overripe fruits and vegetables in the kitchen; keep the compost lid shut tight
Small; black, dull brown, or yellowish; walks in jerky zig-zag motion
Lives around drains, sewers, and garbage cans
Wet, moist, unsanitary areas
Fix any water leaks and keep the area clean & dry
Best Ways to Get Rid of Gnats
Use all 3 of these methods simultaneously to wipe out existing gnats and prevent further infestation.
1. Eliminate the Source and Their Potential Breeding Ground
Clean up your kitchen, seal your drains, and replace your potting soil.
For fungus gnats: Fungus gnats live and breed in the soil of your potted indoor plants. Remove dead leaves on top of the soil. If you suspect mold or fungus, replace the pot liner, the soil, or both. If the root has rotted, consider replacing the plant altogether.
For fruit flies: Remove rotten or overripe fruit from the kitchen. Dispose of all organic foods outside. Tie the plastic bag tightly and properly close the trash bin to prevent gnats from getting attracted to the smell and breeding inside the trash can.
For phorid (drain) flies: If you see bugs in your kitchen that aren't fruit flies, they are likely phorid flies (or drain flies). These insects can only breed in moist areas, typically in drains or where there is leakage. Wipe down the outside of the pipes, fix any leaking pipes, fill and cover crevices and holes where moist dirt can get trapped, and keep your kitchen and bathroom dry.
2. Kill the Larvae and Adults to Prevent Multiplying
To kill the larvae and stop the cycle of procreation, find their breeding ground.
For fungus gnats: The best method I've found is using a combination of steel wool and yellow sticky traps in my potted plants. I cover the top of the soil with to shred emerging baby gnats and adult gnats that enter the soil to breed. I recommend getting medium coarseness or higher, and don't get the steel wool sponges because those have big holes that are easy for flies to get through. I also hang these coarse steel wool on the plant to catch flying gnats loitering nearby. This combination ensures that I kill every single gnat possible. Trapro Sticky Fly Traps
For fruit flies: Fruit fly larvae live in fruits, so just dispose of infested fruits in your kitchen and refrigerator. Hang up those sticky fly traps to catch existing ones.
For phorid (drain) flies: Drain fly larvae live in the sludge and film within your drain, but they may also breed inside the dirt that covers the outside of the pipes. Wipe down the outside with soap and water, and then do another wipe down with distilled white vinegar.
To kill the larvae inside the pipes, I used this . I used the whole gallon over the course of a week, and my kitchen was completely clear of gnats after that. The product is a gel that traps flies and larvae and then kills them with the active ingredient, citronella. I would pour some down the drain at the end of the day and cover the drain with a glass bowl to prevent escapees. Then I would run hot water for 5 minutes the next morning to clear everything out, and then repeat the process again that night. I did this for 6 days. Drain Treatment from Green Gobbler
3. Water Plants With a Hydrogen Peroxide Solution
To kill fungus gnat larvae on contact, water the plant with a mixture of 1 part hydrogen peroxide (3% solution) and 4 parts water. Once you pour the mixture into the soil, you should see some bubbling, which indicates that the solution is working.
4. Apple Cider Vinegar Gnat Trap
This is an efficient natural and homemade way to kill adult gnats without using harmful chemicals. The best part is that this works on all types of gnats.
How to Make a Gnat Trap:
- Pour apple cider vinegar and a bit of dish soap into a jar or cup and mix it thoroughly. The smell of apple cider vinegar attracts gnats like crazy and the soap prevents them from flying, thereby drowning them inside the cup.
- Cover the cup with plastic wrap and poke holes in it with a pen. The holes allow the gnats to crawl into the cup.
- Dump out the contents after 2 days, and start fresh. Do this repeatedly until you no longer see gnats inside the jar.
Note: You can also use beer, wine, or ripe fruit instead of apple cider vinegar, however, you may attract ants, so I recommend sticking to apple cider vinegar.
How to Prevent Gnats
- Don't overwater your plants. Let the soil dry out between waterings.
- Remove dead material on top of the soil. Pick up and discard dead leaves, twigs, flowers, etc.
- Don't leave food out. This means washing your dirty dishes and drinking glasses. Even a slight hint of juice, wine, or sauce will attract gnats.
- Get rid of damp areas. Fix your leaking pipes and faucets. If there is condensation on the pipes, insulate it by getting a foam insulator.
- Cover your trash cans. You should take the trash out as often as possible. Stinky trash cans are a haven not only for gnats, but other creepy crawlies as well.
This article is accurate and true to the best of the author’s knowledge. Content is for informational or entertainment purposes only and does not substitute for personal counsel or professional advice in business, financial, legal, or technical matters.