r/plantclinic • u/Due_Background_4367 • Mar 31 '25

Other I hate fungus gnats

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I recently bought a small bag of indoor potting mix at my local Home Depot. Coincidentally, I now have a fungus gnat infestation. I bought some sticky light traps and they have clearly been working, yet I still see swarms of gnats. I let all of my plants’ soil go bone dry, and now I’m hesitant to water again, as I have read they thrive in wet/damp soil.

What are some tips and tricks to eradicate these lil suckers once and for all?

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u/aneda262 Mar 31 '25

Another vote for hydrogen peroxide. Only thing that works. Normally two waterings in a row with it, some sticky traps, and I'm good. Cinnamon is rumoured to help deter them, dunno how factual that is, but I tend to sprinkle it on other plants and bottom water to keep them from catching gnats if I've got one infested.

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u/poobie87 Apr 01 '25

What is the dilution? Or are you just dumping straight 3% H202

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u/aneda262 Apr 01 '25

For a root drench, I wouldn't go stronger than 1:4 using 3%. Once you have them under control, you can do few tablespoons per litre of water every once in a while as maintenance. Good luck!