Has your house suddenly become inundated with “fruit flies” even though you don’t have any fruit out? Do you find them all over your house, even in the bathroom? They probably aren’t fruit flies; they are more likely fungus gnats.
Fungus gnat eggs are naturally found in most soils but it takes just the right conditions to make them hatch: warm, wet soil. Over-watering your houseplants during the winter months when your house is warm can create that condition.
During the late fall and winter months, houseplants are growing more slowly and require less water. To help prevent fungus gnats, be sure to allow your houseplants to dry between waterings, especially the top 1-2 inches.
You can also add some insecticidal soap to your watering. The soap essentially coats the eggs and prevents them from hatching. Neem Oil will also work. (Be sure to follow the manufacturer’s directions for application.)
Keep in mind that adult fungus gnats are attracted to undisturbed standing water, which is why you may notice them more in the kitchen, bathroom or even around your fresh cut Christmas tree. Unlike mosquitos, the adult gnats do not lay their eggs in water alone.