When you water? If they seem to hang out on the soil surface or around the edges of the pot those are probably fungus gnats.
Mosquito dunks are the way to get rid of them:
Mosquito dunks are the way to get rid of them:
I just throw 1/4 of a dunk in the 5 gallon bucket every 3 weeks or so to keep the gnats away...
If I have an active gnat infestation, I'll use half a dunk in the bucket for a little more killing power, then
I go back to 1/4 of a dunk to keep the growspace gnat-free...
A quarter of a dunk is equal to 1 tbsp. of the bits, if you decide to do it this way.
The reason I do it this way is that it takes 24 hours for the bacteria from the dunks to populate the water, and I don't want to have to fill a gallon jug 24 hours in advance of when I water the plant, so I just treat 5 gallons at a time, and the water is always ready to use..
Dunks (or Bits) are made with a bacteria (BTI) that kills the gnat larvae in the soil.
Harmless to the plants, and just about everything except gnat and mosquito larvae...
Dunks are easy to use- just soak one in the water you're going to use on your plants (I use a 5 gallon bucket) It takes 24 hours for the BTI to populate the water.
Then, just water the plants normally with the BTI treated water, and within 2 or 3 waterings, the gnats will be a thing of the past in your grow room.
You will still have a few gnats until the adults die off, but once they're gone, they're gone!
The larva are what does the harm- they eat roots- but the gnats themselves are harmless to your plants-the adults don't eat, they only drink, so they're just an annoyance...but if you do the dunk thing, that annoyance will soon be gone for good...