Gnats in House in Winter: Quick Solutions to Rid of Them

As winter sets in, you may notice an unwanted guest. A swarm of gnats in your house during the colder months can be a nuisance. Understanding these tiny insects and their habits will help you effectively deal with them and maintain a gnat-free environment.

Gnats thrive in damp, moist conditions, such as over-watered plants or areas with high humidity. In the winter, these indoor pests seek warmth and shelter, leading to an infestation in your house. There are various types of gnats, such as eye gnats and fungus gnats, which may be responsible for this issue.

To tackle the problem, some common measures to control gnats include:

  • Reducing excess moisture in your home
  • Regularly removing any damp, decaying plant material
  • Avoiding over-watering houseplants
  • Utilizing traps, pesticides, or natural remedies

Stay vigilant, and keep your home gnat-free by adopting these preventive measures this winter season.

Understanding Gnats in Your House

Types of Gnats

  • Eye Gnats: Non-biting flies in the genus Liohippelates, also called grass flies, eye flies, or frit flies1.
  • Fungus Gnats: Slender, somewhat mosquito-like flies about 1/10 to 1/8 inch long, with dark-colored antennae and long legs2.
  • Buffalo Gnats: Also known as black flies, small, 1/16- to 1/8-inch-long, humpbacked black flies3.

Life Cycle and Metamorphosis

Eye Gnats:

  • Eggs laid in loose, sandy soil1
  • Larvae develop in soil1

Fungus Gnats:

  • Gray or orange-to-yellowish in color2
  • Eggs are yellowish-white and tiny4

Buffalo Gnats:

  • Females feed on blood, males on nectar, and plant sap3

Weather and Warmer Months

Gnats are more prevalent in warmer months. In winter, managing gnats in your house can be achieved by adjusting temperature and humidity, removing breeding grounds, and using traps or repellents.

Method Pros Cons
Temperature Non-chemical May affect comfort
Humidity Non-chemical May affect comfort
Breeding Grounds Long-lasting effect Increased cleaning efforts
Traps Effective Unsightly
Repellents Protection Possible side effects

Footnotes

  1. Clemson University Home & Garden Information Center 2 3

  2. NC State Extension Publications 2

  3. Illinois Extension 2

  4. Darkwinged Fungus Gnats | NC State Extension Publications

Reader Emails

Over the years, our website, whatsthatbug.com has received hundreds of letters and some interesting images asking us about these insects. Scroll down to have a look at some of them.

Letter 1 – No-See-Ums

 

What bug is unseen to the eyes that invade?
February 2, 2010
What kind of bug bites hard, leaves whelpes, like a rash, but can’t be seen?
Not scappies! I thought dust mites but be treated for that and still have the problem. We thought flees, but have seen none! it’s at night when they attack, we thought maybe a nat or something.
Can you help me? DeAnn
los angeles

No-See-Ums, seriously.

Oh my God!  I first thought you were make’s fun of me, then I discover there really is a bug call no-see-ums, lol…  Thanks!

Letter 2 – Gnats

 

Hello, Bugman;
We have several houseplants: jades, aloes, hibiscus, etc, which seem to be attracting or generating extremely tiny flying black gnats or fleas that can barely be seen. We have washed down the plants to no avail; the almost invisible slowly flying bugs are still showing up in many areas of the house. Any idea of what this pest is and how we can control or eradicate it? Thanks so much for your help!
T.E. Boston

Dear T.E. Boston,
My money is on the Black Gnat, Bradysia impatiens. This is a type of root gnat from the Family Sciaridae. The adults are the tiny black gnats that flit in your face while you are watching television and that always seem to get stuck in fresh paint, writes Hogue. He continues "The larva lives in decaying plant material, such as compost, peat, and sphagnum; it also commonly infests the roots and stems of various herbaceous plants. The insects may develop in the media used for potted plants, which explains its mysterious appearance indoors." A mild soapy water used to water the plants might help. Other natural methods to try are an infusion of crushed garlic in water, or nicotine in water. Try soaking some cigarette butts in water and using that when you need to water the plants. The same can be done with the garlic infusion

Letter 3 – Gnats

 

I live in the midwest and recently relandscaped a good portion of my lawn and had bluegrass sod laid. ok so it was a very warm dry winter then 2 days after sod was laid the spring rains started and just keep coming. Problem is 2 monthes later the rains still come 1 or 2 times a week. there are lots of mushrooms growing in the new sod but that dosen’t bother me i know it will dry up soon. the problem is the sodded area seems to be infested with small dark colored flying bugs larger than gnats but smaller than the average house fly.the sod is still deep green but im worried that this could be a damaging infestation! what kind of insecticide should be used ? can you tell me what kind of bug this could be? thanks in advance!
Robert Bouchard

Dear Robert,
Many nonbiting gnats including Root Gnats (Family Sciaridae) and March Flies (Family Bibionidae) spend their maggot form eating decaying plant material such as compost, peat and spaghnum. They are scavengers who often live among the roots of grasses. There was probably a substrate of manure and compost laid beneath your sod, and that is where the flies are breeding. They will not damage your lawn as they do not feed on the living grass.

Letter 4 – Gnats

 

What is the tiny fly type bug that comes in through the window screens and hangs out on the window glass or ceiling. They almost look like a small fruit fly but they are not. They hang out in the grass as if you water your lawn or walk through it they disperse. Just tons coming in the garage screen door. I’ve been swatting them for almost a week now. Live in NY state and it has been dry and hot. Thanks

Dear R.
Any number of gnats are small enough to enter through the openings of window screens. The Black Gnat (family Sciaridae) is tiny, about 1/16 inch, and often flits in one’s face while watching television or gets caught in fresh paint, or causes despair when they appear in bowls of breakfast cereal. The larva live in decaying plant material, often being numerous around compost piles, and they are also known to infest the roots and stems of various herbaceous plants. Since you haven’t complained of itchy bites, you can be thankful that you aren’t being plagued by nasty no-see-ums, so count yourself lucky that you just get benign gnats.

Letter 5 – Hessian Fly

 

Found this critter in our yard this year (we live in Texas). Sat down on the garden swing and then found we were covered in them. Have never seen one before. Sort of looks like a cross between a spider (the round torso) a fly (the wings) and a mosquito (legs and stinger like head)? Sorry I couldn’t get a closer pic. The camera wouldn’t focus on the bug and not the leafs that close. Haven’t hung around long enough to see if they sting or not.
Sandra

Dear Sandra,
It is difficult to be certain with your photograph, but I’m guessing you encountered a swarm of Hessian Flies, Mayetiola destructor, an agricultural pest in the Midge family Cecidomyiidae. The maggots do serious damage to wheat plants. Adults are small (1/8 to 3/16 inch long), dark or red-tinged, gnat-like flies with long legs and antennae. The insect got its common name, according to Lutz, when the European insect was first noticed on Long Island shortly after the Hessian troops landed there. It is especially plentiful in Texas. Here is a downloaded Photo by C. Hoelscher.

Authors

    by
  • Bugman

    Bugman aka Daniel Marlos has been identifying bugs since 1999. whatsthatbug.com is his passion project and it has helped millions of readers identify the bug that has been bugging them for over two decades. You can reach out to him through our Contact Page.

  • Piyushi Dhir

    Piyushi is a nature lover, blogger and traveler at heart. She lives in beautiful Canada with her family. Piyushi is an animal lover and loves to write about all creatures.

1 thought on “Gnats in House in Winter: Quick Solutions to Rid of Them”

  1. My house has been invaded by 2 species of flying insects about 2 years ago and about the same time as far as I can tell. Fungus Gnats(Mycetophilidea & Sciaridae) and Phorid Flys(Phoridea), Also about that time I had the tiny black Fleas brought into the house by a relative with a dog which is not something I would have let happen if I would have been the one to answer the door. These Fungus Gnats get into my hair and bite or sting with authority, the flea bite is also quite painful. I have been using “TEA TREE OIL” & an environmentally friendly spray which helps, but when I think I am about to win the war it turns out only to be a skirmish. My main observation is this, I have found all over the bedclothes and my own tidywhities what look to be under magnification (a 50 power jeweler’s loop) very tiny thread which is wrapped so that it resembles a tiny skein of knitters yarn only made up of a number of different colors in one skein (usually BLUE, RED, GREEN & BROWN). To the NAKED eye they look like a speck which would fit though the eye of a needle. One thought I have is that this is the waste from the tormentors. Thanks for having a site like this so the folk, such as myself can find help and hopefully regain a normal life. One other observation is that my wife is not bothered by these DEMONS at all and thinks I am CRAZY. …RADARONE…03/12/2019…

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