I've been struggling to eliminate soil gnats from my plants, and I'm not sure what else to try. Here's what I'm currently doing: using a gnat trap machine, sticking multiple gnat traps on at least five plants, spraying a tea made from systemic granules on the topsoil every week, and I've only been bottom watering all my plants for over three months. While I've noticed a decrease in the number of gnats, they're still around. Does anyone have additional tips on how to control these pesky gnats? Thanks!
3 Answers
If the infestation is bad, consider dumping the soil and repotting your plants. Sometimes, that’s the best way to start fresh and get rid of those stubborn gnats!
I keep a mosquito dunk in my watering can. I fill it up in the morning and let it sit all day before watering in the evening. The dunks dissolve slowly, so they last a while. Additionally, you could repot with fresh soil and soak the roots in a diluted peroxide solution for a short time to kill any eggs or larvae hiding out in there.
You could try spraying a diluted peroxide solution on your plants. It works wonders, and you should see those gnats disappearing within a few days! Just make sure to find the right dilution ratio so it doesn’t harm your plants.
Do you have any specific ratio in mind? I accidentally killed a plant using a 1:3 ratio of peroxide before.

I’ve got over 30 plants, so that would be a huge job for me!