Gnats

• The gnats that are usually found in and around houseplants are fungus gnats. Fungus gnats thrive on the fungi, algae and decayed plant matter in the top levels of potting soil, where they lay their eggs.
  
  

Causes

• Fungus gnats are usually the result of overwatering and poor potting soil, both of which provide the environment these gnats need to grow. Gnats also appear on houseplants brought in after summering out of doors.
  
  

Control

• Controlling fungus gnats means getting rid of the conditions that they need to grow. As potting soil ages, the matter breaks down. Repot plants in fresh soil to remove the dead matter in which gnats thrive. Water plants only when the top one to two inches of the soil is dry. If gnats are present in your outdoor plants, repot the plants in fresh soil before bringing them inside.