Hydrogen peroxide for a small case of fungus gnats

I am heading into my first week of flower and I noticed that I had a couple little fungus gnat larvae on top of my soil, and in the crease of my leaves, etc. I heard once that 3% hydrogen peroxide can be used to help kill fungus gnats and their larvae? If this is true what ratio would I use to a gallon of water or half gallon of water? Thank you for the help. Ps I have eased up on the watering as I’ve read that this can be a sign of over-watering.

Take a few potatoes cut them in half and put them on top of your pots… the Nats will be attracted to the potatoes more than your soil… you will start to notice little worms sticking out of the potatoes telling you that they’re full and getting ready to transform into flying bugs… that’s when you need to discard them and replace them with new cut in half potatoes … eventually they will go away… :wink:

:v: :sunglasses:


Ok. Thank you. I’ll have to try that. I heard about that in one of the articles in the past and totally forgot. I’ll give it a shot. it definitely can’t hurt anything and it’s less invasive hydrogen peroxide I imagine.


And, change your watering practices because that’s a sure sign of wet soil that never dries out.


Interesting, I’ve never seen a fungus gnat or their larvae on a leaf, its always been on the medium. If you do use HP for this the ratio is 1 part HP and 4 parts water. HP will only kill larvae, not the adult gnats and they will continue to reproduce quickly. I always have to use it in conjunction with something else like sticky traps to get the adults. The potato sounds like a great idea! Watering with small amounts of peroxide is beneficial in other ways too @neckNflu

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Diamatreous Earth works good, buy the food grade only!.. it has to be good grade or it will be toxic… sprinkle the DE powder on top of soil… some folks use a duster to dust leaves and branches… worked great for me @neckNflu


Thanks to all of your responses! I appreciate it. I ran into this little snag because I was trying a new medium called coco loco bush doctor. I guess, according to the bag, it retains more water so you’re supposed to water less. Took me a little while to get a hang of it. Think I got it corrected now but of course the couple over waterings I may have done started this little problem. I have potatoes and yellow strips up at the moment! I believe I caught it at the very beginning stages. Nothing flying around or anything in the room.


I had them bad using “5gal air pots” all the holes in the sides gives easy access to the soil even if u cover the top with perlight. Or pumice stone or even sand 1.5 thick helps controll them also.
Along with making sure your soil is dry between waterings completely.
Potatoes was also suggested to me and i belive worked some too, in conjunction with sticky fly strips layed near soil between plants. Replace when full. Surprised me how fast they fill up, didnt even kmow i had that many.
Also more fans at soil level helps keep them from flying. They only effect the roots when they get bad, BUT they will stick to sticky buds and leaves when they are getting frosty. Its very very time consumming sitting with tweezers and picking them off everytime u visit your room.
A bowl of apple cider vingar will help too as they land in it and drown. Good luck if these dont work tag me and ill send u a picture of the organic stuff i ended up buying. The combination of it all worked! So dont give up.