Fungus Gnats in my grow tent

My plants are 31 days old, none of them have any signs of damage or stress but I have seen evidence of these annoying pests. I generally will only see one flying gnat and have seen maybe one or two crawling on the soil. They generally pop up after I water, but seem to go away after a couple days and the soil dries out a bit.

Any tips or tricks to help remedy these pests?

Use mosquito bits


I mix diatomaceous earth in my soil, and have yellow sticky pads, you can mix mosquito bites in your soil also.


I use diatomaceous earth,yellow sticky pads and neem oil,I spray it on and also water it into the soil water.It stops the breeding cycle and is good for your plants.

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I’ll have to give it a try if I encounter the problem again! I read some forums and ended up putting out a dish of coffee with sugar and the fungus gnats went to it. Haven’t seen any in about a week so it’s helping for now. I was way hesitant on using the mosquito bits…just something about a product that has a do not inhale warning lol

Ya,I have used mosquito bits,but they didn’t seem to help against the fungus nats,but the neem oil works. I also used apple cider vinegar in a dish,with limited success. Those little buggers are nasty tough.

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Wanna know what gets rid of gnats?? Worm casting. Put some on the top of the soil and it will get rid of them. I mix it with my soil and also add some everyonce in awhile. Ive personally dealt with it myself and also did research plus castings will help a plant thrive more. Castings also help stabilize ph akd many other good things


I have about 15 house plants besides my grow, and long ago began my battle with fungus gnats after someone gifted us a plant which must’ve had them. I had never had an issue prior, once this plant came in, it was insane; they spread to every other plant in the house and got so bad you could see them in the air.

I’ve used a 5-part attack against them and as of today, I’d say I’m about 95% of the way to full eradication. It takes fighting them steadily for a while to make sure they don’t have a window to build back up. One adult can lay 200-300 eggs, so it’s a big battle.

Part 1: Set up some of those yellow sticky fly paper traps around your plants and near windows.
Part 2: I also used a mechanical catcher from Amazon called “Katchy” which uses ultraviolet light at night and a fan to suck them in. It’s very effective:

Part 3: Neem Oil both sprayed onto the plant and onto the soil before AND after watering; before so watering pulls some into the soil, after to help keep a barrier on the soil surface where eggs are laid.
Part 4: Top-dress the soil with Mosquito Bits, watering draws this down into the soil which kills the larvae.
Part 5: Let the top 2-3" of soil totally dry out between waterings. The eggs and larvae need water and moisture to develop and survive.

Following this over time they’ve become less and less and I only see a random one or two in the house here and there now. I’m keeping the assault up until there are none left! As far as my grow tent being set up new in a house with an existing fungus gnat problem, it’s been a very minimal issue. I have seen a handful of them in the tent, but as I’ve gotten it under control in the house and only using neem oil on the plants in the tent, it’s been a couple weeks now without a single gnat in sight inside the tent. :grinning:


That’s great stuff man!! Thank you. Something I will definitely include in my soil mixture on my next grow. I think this fungus gnat issue came with the soil I got cause my plants are in a very controlled environment so I can’t see how else they would have gotten in. I watered with a neem oil ratio of like 1 tablespoon to 2 gallons a few days ago…haven’t had any sightings since but I love the worm casting idea. Organic and practical.

Man you had A LOT of those things. I would see one or two flying gnats at the most. I think the problem came with the soil though so on my next grow I will probably pre-wet with neem oil mixture and probably add worm castings. I ended up doing about a table spoon of neem oil to 3 1/2 gallons of pH water and just soaked the soil a few days ago. Plants didn’t respond adversely and haven’t seen any gnats in flight so hopefully it’s under control for now.

I gotta get me that sticky fan!!


Yep, I had a full on invasion in every plant in my house before I realized or learned what was even happening. First time ever having them! Persistent little buggers, and if you miss ONE adult and get lazy, the cycle can restart. Don’t get comfy and slack on your preventative measures if you start seeing only a few around! Those few can still be very very dangerous in terms of things getting worse.

Yea i had the gnats come in my soil i bought aswell. I always buy a bag of castings to mb add eith perlite and other goodies amd they end up disappearing

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