How do you keep small flies from breeding in your indoor potting soil.

Last time I bought an indoor plant and 2 weeks later I had a ton of tiny flies/knats in my home and discovered they were coming from the soil of the new plant. How do you treat the soil to discourage that?

  4 answers
  • Janet Pizaro Janet Pizaro on Jan 03, 2018
    You have to re-pot the plant in fresh soil.They are fungus gnats that lay eggs in the soil. Spray alone will not be enough control.

  • The plant was contaminated before you brought it home. Needs to be reported with fresh soil. Run the roots under the faucet carefully to wash before replanting in fresh soil. Do this to any plant that seems infected.

  • Linda Linda on Jan 03, 2018
    Those are fungus gnats and they have two stages to deal with (under ground and above ground). For the adults which are gnats you can get yellow sticky flytrap paper or make your own with Vaseline (a little messy, but it does the trick). Take a yellow piece of cardboard (or plastic if you have it) and spread the Vaseline on both sides. Then hang the cardboard near your plant or create a stake to push into the soil.
    For the underground larvae, you need to water with a little bit of neem oil in your water OR put some chick grit, sand, or very small pebbles on top of your soil so that the gnats get trapped and cannot emerge.
    Good luck. Be vigilant. Give it a few weeks. You may have to re-treat if the gnats are persistent.

  • Jeanette S Jeanette S on Jan 03, 2018
    The first thing I would try would be to set the plant outside and mix up some Dawn dishwashing liquid and cold water...about the amount you would use to wash a pan of dishes. Pour it over the plant, making sure you get the under leaves covered even if you have to spray underneath. This is the old home remedy my mom used to keep the bugs off her flowers and shrubs...every night she emptied her dishwater over them!