are they black?
just kill them with your finger, thats what we did.
we had them on ours.
any spiders, leave in there to kill them too.
after your plants get bigger, they will go away.
how long have you been growing for?
fungus gnats can be a problem because their larvae grow in the soil and can eat your roots.
they usually show up due to continually wet soil
use yellow sticky cards to trap adults and get something to kill fungus gnat larvae for your soil and let the soil dry out in between waterings