They are probably those little fungus gnats that like that wet soil in your
plant pots. I was told long ago by an orchid guru to sprinkle cinnamon on
the surface of the soil and they disappear. I don't know if it kills them or
drives them away but it works for me when I occasionally get an infestation
of these critters.

Val


Thanks for the cinnamon info, Val.
Sue in Mi. (Zone 5)