Fruit Flies

Are they a problem? If so, how to get rid of them?

More than likely you have fungus gnats, they are super common in all house plants. They are mostly just annoying but can cause issues if their population gets too big. I've heard of ways to check like putting a cut potato cube on your grow media, and the larva will come to the surface and eat it, and you can see them on their and stuff, but I've never done it. Takes some patience to be done with them, but I used a combination of yellow sticky traps, and mosquito dunks in my res. They are like 10 bucks at home depot you google to find it. This is probably the cheapest way. In my res I put the dunks in panty hose with the end tied, because they don't fully dissolve and are kinda messy, especially if you use pumps. I would spot spray em here and there, but I was done with them in about 3 weeks and they just never came back. The stickies will kill the flying moms, and the dunks in the water kill the babies in your grow media that like to eat roots.

If I happen to be wrong and it is just fruit flies, I don't know that they are a problem, and not sure where they plant their eggs. Gnats like moisture, so other tricks people use are to let their dirt get extra dry, or a layer of sand on top of their dirt so the gnats can't lay eggs or something, i dunno. When I had gnats they liked to hang out by the drain holes of my plants in soil.

Anyway good luck, hopefully that helps!.

Thanks. Im using soil though.

Could be gnats or fruit flies I guess. Could be from bringing them into the sun daily.

Fruit flies do resemble fungus gnats at first but they are easy to distinguish upon a closer look , the gnat is a bit larger and darker .. Each is easily caught using sticky traps as mentioned but the fruit fly is easier to catch if you have ripe fruit .. Cannabis is not something fruit flies eat luckily but fungust gnat larvae will eat roots if there is nothing else and then in numbers they can do some damage left unchecked .

Either way in a few weeks when the temps of fall return they will all be at there worst as they end another season with a bang ..

Put a layer of perlite on top of your soil @1"-2" they don't like crawling through the perlite to lay there eggs in your soil. Block all other drain hole best you can to keep them out.
Run your soil on the dry side. The fungus gnats like wet conditions.
Diotomaceous earth works well to as a preventative measure to keep the bugs out.