I might consider trowing away all my house plants… it started with a 6y old monstera that developed flies last Xmass and can’t get rid of them since. The big monstera died because I took her outside to free the flies and it was too cold for her. I managed to save a bit of her (her son) that I washed off all the soil and still developed flies after a while. Then got another monstera from Lidl(UK based) and that one got flies. I also got spider plants that don’t seem too affected. A photos that’s holding up. I took off some soil of the top where there suppose to be egg flies and even repotted them. Nothing. Used chemical products… nothing. Any advice please? It is important for me, i already cried a couple of times over this situation. Can I grow everything in water???
by adina532c2
10 Comments
Those yellow sticky traps are clutch for monitoring but they’re just catching adults, the larvae in the soil keep the cycle going. A half-inch layer of sand or fine gravel on top of the soil smothers them before they can crawl out, works better than chemicals most of the time. For the ones you’ve already washed and repotted, letting the top two inches of soil go bone dry between waterings usually breaks the loop since they need moisture to breed.
Have you repotted with fresh soil yet? Also what kind of soil are you using b I know you said you’ve washed off the soil but have you tried new soil? Repotting with fresh soil after removing the plant and giving it a good rinse, maybe a spray of 70% iso when it’s out of the soil, avoiding roots and then repotting it. Might be worth it to buy some new chunky soil to avoid pests and save yourself the headache of trying to reuse the soil if that’s what you did
Try beneficial nematodes. I struggled with fungus gnats for months and then ordered beneficial nematodes online and they were gone within 2 weeks
Predatory insects that target fungus gnat larvae is a good control method to cut down the population fairly quickly.
The base reason for an infestation of flies is almost always overwatering, though. Fungus gnats can get brought in when you open the door/window/bring home produce etc., so fresh soil is only helpful in cutting down their numbers initially but won’t permanently solve anything without other changes.
Allowing the top two inches of soil to be dry before watering and NEVER having soggy soil will cut down numbers massively because they need the moisture to proliferate. If your soil mix is holding too much moisture, amend it with things like orchid bark or other chunky aroid mixes to make it less hospitable to the gnats. If you do these things in combo with the appropriate predatory insects, you’ll not need to worry about infestation. There will almost always be a few kicking (I’d say i notice about 6 as a max with my houseplants), but they serve their purpose and don’t cause any real annoyance unless their population booms.
Try adding cinnamon on the soil. It kills fungus and flies. It worked with every plant I had.
Those look like mosquitoes…
Unless they’re a small variety of flies
If you try watering with mosquito bits/dunks, make sure to let them soak into the water for a while. I tried just mixing them in the water then immediately water the plants, and it did nothing.
I broke up the mosquito dunk under the water and let it sit for about an hour, then watered with it. Every bug was dead by the next morning.
A lot of the suggestions you’re getting here are BS or overkill.
Google “BTI tea”. It’s the cheapest, easiest and most effective treatment for gnats.
I tried the sticky traps, along with the Zevo blue light sticky traps and caught 100’s. My mind was blown by how many were actually flying around my home. We ended up disposing of $200 worth of plants purchased at Home Depot. I’ll never buy their frigging palm trees again!
I solved with neem oil and later added gravel on top of the soil