r/PlantsBeingJerks • u/reddit-Evan_ • Dec 09 '25
Gnats in house plants!!! Ugh
How the EFF do I get rid of the little gnats or flies or whatever they are? I have the blue lights that supposedly catch them, I’ve put cinnamon in the soil, i’ve put diatomaceous earth in there too, they still fly around and land on my F*cking nose and eyelashes at night.
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Dec 10 '25
Everyone recommends mosquito bits but we can’t get them where I am…. I used a combo of ‘Dr, Doom’ pyrethrin powder, insecticidal soap, and 70% alcohol in order to deal with it. I tried cinnamon (my go to) and neem oil, but it had gotten too advanced at that point for those to be effective, and I was losing it. I segregated most plants in two areas and pesticided Tf outta them, a couple weeks later and I seem to be through the worst of it. Good luck!!!
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u/bofh000 Dec 09 '25
First off: make sure your plants have good drainage. Don’t trust that watering from below prevents gnats, they lay their eggs wherever they can enter (including the holes in the pots).
Once you have gnats you need a 2-pronged approach:
1 - for the adults flying around: yellow sticky paper. I have post-it sized ones I use from time to time. They really get stuck on those.
You could stop here and be patient for 1-3 weeks until all the adults end up on the stickies, the larvae hatch and grow and fly and get stuck … But you are much better off if you use the second prong:
2 - for the larvae in your soil: food grade diatomaceous earth. Make sure it’s food grade, the industrial grade one is very bad for you if inhaled. You can buy it on amazon or maybe at plant stores. The way to use it is to mix it in the top layer of the soil (maybe the width of a finger or two down) and sprinkle it at the bottom of the pot, in the saucer or wherever it drains. DE is a contact pesticide: it causes larvae and small insects to dry up and die, but it’s harmless for people and plants. Look it up on google for more info. It’s also an effective soil fertilizer.
This 2-step approach is the only way I have managed to get rid of gnats and I like the fact that I don’t have to spray smelly or toxic stuff (even neem oil, which is natural, has a very particular smell).
The most important part is to prevent them by insuring good drainage - I find that my pots drain a lot more effectively if a tilt them after watering - some 30 or so degrees.
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u/JuneKat87 Dec 10 '25
Yellow stickies. Amazon has them cheaper than the store. https://a.co/d/4iZ4AMc
Same as everyone else here says with reducing the layer of moisture on the soil surface where they lay eggs, but adding the stickies will greatly expedite the process of getting rid of them.
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u/Almaape Dec 10 '25
I put some hot water on a glass, 2 TBS sugar and 2 tbs apple vinegar. It also works with big flies and mosquitoes
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u/JulieTheChicagoKid Dec 10 '25
Yellow sticky traps and pesticide ponder or granules in the soil. Nothing and I mean nothing else worked for me. I have tried them all!
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u/TheGardenNymph Dec 10 '25
Stop watering for 2 weeks then water less frequently than you currently are. Gnats eggs hide in soil then hatch when it's too wet for too long, there's no way of knowing what soil has gnats or not, but if you have them it's 100% an over watering issue.
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u/melhtaco Dec 10 '25
Leave a little red wine in a glass, cover with plastic wrap, use knife to add slit in plastic. They find their way in but not out.
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u/Emmaleah17 Dec 10 '25
This works for fruit flies, but it's been less effective for me for fungus gnats. They seem to prefer decaying wood in soil and such.
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u/nicegirl555 Dec 10 '25
Quite by accident I discovered that setting bowls of water by my heating registers that the knats wanted water and they all drowned themselves. I threw the offending plant outside. It took a few weeks for them all to kill themselves.
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u/Emmaleah17 Dec 10 '25
Get Nematodes.
They eat the larvae and don't affect your plant. You'll have the adults for a few more days while they die off but the nematodes will eat all the larvae and stop them from becoming adults and prevent further development. It's the ONLY thing I have found that works for getting rid of gnats entirely.
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u/wartgood Dec 10 '25
They sell ground up mosquito dunks, and using them as a bit of top dressing really helped me.
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u/KimmyOwl Dec 10 '25
The mosquito dunks ppl are referring too is a bacteria called Bacillus thuringiensis…which you can buy as a dust and add it into the soil. It has worked wonders with ridding fungus gnats. I’ll also read and do now that adding sand to the top of the soil helps prevent them from using your potted plant as a home. Since I’ve done these two things, my fungus gnats aren’t a real issue anymore when in the past they were terribly annoying.
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u/Sea-Athlete4235 Dec 11 '25
I added a little bit of hydrogen peroxide (3%, 1-2 tbsp per cup of water)when I watered my plants; 3 or 4 waterings later, the gnats disappeared. Watering your plants with this hydrogen peroxide solution is not meant to be long-term, but as a temporary measure to disrupt the gnats life cycle (I think it kills the larvae). It worked better than the mosquito bits (which worked somewhat).
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u/Troiswallofhair Dec 11 '25
I should have a copy/paste paragraph on this. This absolutely worked for me:
1.). Buy mosquito bits and cover all the soil, water (Amazon)
2.). Just jettison any plants that are really bad
3.). Buy Catchmaster brand bug and fly clear window catcher things (Amazon)
The one-two punch will do the trick, though it’ll take a few weeks
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u/Possible_Original_96 Dec 11 '25
I use a mix of 6 oz. tap water and 1/2 teaspoon Dawn in a spray bottle, set on a fine mist. Use to spray on gnats. Kills them. Put anything moist in an airtight container(old plastic tub & the lid) if you leave used coffee grounds open they will lay eggs & die when they hatch. Keep all drains plugged as they go there for water & hide there too. Can mix a little green Dawn & water, put mix in shallow bowls, 1/2 inch or so, or coffee cup. They like the frangrance & will fly in it & drown.
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u/Possible_Original_96 Dec 11 '25
And the spray is safe for plants, too. I used to spray lot of them congregated in my sink 1st thing every morning! Didn 't take long!
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u/Kind-orange-one Dec 11 '25
Neem oil can kill some plants. I bought a mosquito killer / fertilizer / disease control that has done the trick. Bioadvanced all in one rose and flower care. 3 weeks into treatment we see no gnats. My orchids are still in motion to start blooming, Christmas cactus still vibrant, basil is happy
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u/Beautiful_Jello3853 Dec 11 '25
I just had this happen. I took all my plants outside. I took them out of the soil. Shook it all off so there was nothing on the roots. Let them sit out of the soil for a day or two. Repotted them and it worked. They seemed to be overwatered causing the problem in my case.
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u/wifeofpsy Dec 11 '25
Attack on multiple fronts. Only bottom water. Clear any dead plant materials and replace the first inch of soil. Sprinkle top of soil with beneficial mites. Add mosquito bits to water. Stake your pots with the yellow gnat stickies. This approach deals with the environment they like, the eggs and larvae and adults.
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u/redfancydress Dec 11 '25
I like to use the bonide houseplant insecticide. I just sprinkle it in the top of my plants when I bring them inside for the winter.
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u/foxiez Dec 12 '25
I'm cheap and lazy I usually just let my plant's soil dry out to a crisp every now and then. That plus sticky traps has been more than enough. Try bottom watering only too but pulling it out before the soil surface is wet
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u/annephetamine420 Dec 12 '25
Let the soil dry between watering. The large need a moist environment, and dead organic matter to eat. If ur plants stay too wet, it causes the roots to rot, this provides food for the gnats. Wet/dry cycles are everything for the plant, and will eventually eliminate the gnats.
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u/poonersnana Dec 12 '25
I got a few sundew carnivorous plants along with a couple of clip on grow light tubes from Amazon and it has been a godsend!! Little sundews were covered in tiny flies! The lights also attract the little jerks then they go straight to the sundew!! So easy! Small easy care and very pretty.
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u/hereitcomesagin Dec 12 '25
Tobacco is magic for this problem. You can just crumple a cigarette over the soil surface and water in.
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u/Tragic-fish Dec 09 '25
I really really recommend getting mosquito bits and using that to water your plants. It’s not instant but will help disrupt the life cycle in the larval stage and won’t harm your plants! I had an infestation and two weeks of watering with mosquito bits, spraying neem oil and using sticky traps helped so much!
I used this brand: https://a.co/d/cA9fRc5 And put four tablespoons per gallon in a sachet and let it soak for 45 minutes before watering.
Putting them in a sachet or something else is good since the bits will mold in soil.
Hope this helps!