Though they can cause damage to house plants, gnats, tiny, flying bugs that travel in swarms, are usually more of an annoyance than a danger. Out in the wild (or even just in your backyard), some gnats participate in plant pollination. And some species consume garden pests like aphids and scales. If you spend time hiking trails during the summer, you’ve probably been swarmed by gnats more than once. If you’ve ever ridden your bike in hot, humid weather up a mountain steep enough to slow you down to under 10 mph, you’ve probably arrived at the top with a little throng of gnats buzzing around your head (some species are attracted to human sweat). One place, though, you don’t expect to be confronted with a flock of tiny insects is in your house.
Advertisement
Article continues below this ad
Drain flies, fruit flies, phorid flies, and fungus gnats are the four most common kinds of gnats that invade homes.
Fungus gnats show up in overwatered houseplants and in some organic potting soils as a result of decaying matter. Their baby larvae consume roots which can cause the plant to wilt and eventually die. Phorids buzz around garbage and drains, as well as rotting fruits and vegetables. Fruit flies gravitate toward both rotting and fresh fruits, as well as soft drinks, wine, and vinegar. And drain flies congregate around and in drains, sewers, and septic tanks.
All gnats bite but they do not all possess the appropriate mouth parts to penetrate human skin like mosquitoes (which, though a bit gross, can be considered good news.) They breed in large numbers in garbage disposals, trash cans, and drains (among other places).
Here are some ways to get rid of gnats in your house.
Homemade gnat traps are easy to set up; simply fill a saucer with three tablespoons of apple cider vinegar, some sugar, and a few drops of dishwashing soap. Mix the ingredients and leave the saucer (or saucers) out on the counter. Gnats will gravitate toward the sweet mixture, become trapped within it, and die.
You can also make a trap using a piece of fruit as bait. Place an overripe apple, banana, or pear in a bowl and cover it with plastic wrap. Punch a few, tiny, gnat-sized holes in the plastic. Gnats that make their way into the bowl and under the plastic will be unable to find their way back out and will be trapped for easy disposal.
Another effective gnat trap is an almost empty bottle of red wine left open on the counter near the sink. Gnats will dive bomb or crawl into the bottle to reach the sweet alcohol and won’t be able to escape. The theme here, as you’ve probably figured out, is that while gnats seem to be adept at finding ways to get to a sweet-smelling snack, they are really bad at figuring out how to escape the same way they came in.
Plain, old flypaper strips will also ensnare gnats, though they’re rather unsightly and can catch onto things that you don’t want them to; like hair, curtains, and furniture.
If you notice gnats coming out of your kitchen drain or swarming near the sink, clean the drain by pouring ½ cup of bleach mixed with a gallon of water down it. After dumping the bleach, flush with hot water for five to ten minutes.
Make your own spray solution that will kill gnats on impact with one cup of water, one tablespoon of vinegar, and a few drops of dish soap. When you see gnats buzzing around, direct your spray bottle nozzle at them and spritz.
Getting rid of gnats on houseplants
If your gnat problem is focused around your houseplants, employ one or more of these methods to get rid of them.
Cut yellow sticky cards and place them on top of the soil or make mini flags out of them by attaching them to twigs or skewers. Gnats are attracted to the yellow color and will become trapped on the sticky surface.
Containing the fossilized remains of aquatic plankton, this organic powder sprinkled on top of dry soil will trap and dehydrate gnats before they can make their way to the plant roots.
This naturally occurring bacteria kills the larvae of fungus gnats. It soaks into the soil and adheres to the plant roots, causing the plant no harm but killing the larvae when it tries to feed.
If none of the above methods work, repot the plant with fresh soil.
How to prevent gnats
The trick to keeping most any pest (insect or rodent) from entering your home is to seal any cracks, holes, or crevices you find. Repair or replace window screens as needed and try not to leave dirty dishes in the sink for very long. Keep fruit and vegetables refrigerated whenever possible.
Outside, check for any plumbing leaks or soil that remains perpetually damp near your downspouts and gutters as gnats like to breed in damp areas. If you notice a large number of gnats near outdoor plants, drop a mosquito dunk into a watering can or bucket and let it sit for long enough to release its insect-killing bacteria. Then water your plants with the bacteria-laden mixture for a few weeks to kill gnat larvae in the soil. Make sure to use a dunk that is safe for pets and wildlife.
With a little vigilance and regular cleaning, you’ll be able to get rid of and prevent excessive gnat activity inside your house. Those gnats you meet while out hiking or biking, though, are a different story. The quickest way to get rid of them is to speed up if you’re able and maybe even set a personal record in the process. I, personally, can attribute some of my best times while ascending to the desire to get away from pesky gnats.