Enjoying your houseplants but noticing some small flies zipping around the soil? They may be fungus gnats. These dark, delicate-looking flies look similar to mosquitoes. They’re attracted to light, so you first might notice these pests flying near windows indoors. Check your plant pots. If the soil in the pots is overly moist, fungus gnat larvae could be feeding on the plant roots.
Prevent these pesky bugs by providing good drainage and not overwatering your plants. Allow the surface of container soil to dry between waterings. Avoid using incompletely-composted organic matter in potting media unless it is pasteurized first, because it will often be infested with fungus gnats.