Does anyone have a way to eliminate fungus gnats in houseplants?

For starters, I live in a condo and have very limited outdoor space. I do have a lot of houseplants that are thriving with grow lights and really want to try growing some indoor herbs. However, no matter what type of soil I use I always wind up with fungus gnats. Any suggestions on how to get rid of them?


  • naomi.kohlmeier
    naomi.kohlmeier Posts: 380 ✭✭✭

    We use hanging flytraps. Also we try to keep the top of the soil dry.

  • Monek Marie
    Monek Marie Posts: 3,535 ✭✭✭✭✭

    I use cinnamon or chamomile on the top of my soil to control bugs. and under watering.

    And fan might help too.

  • shllnzl
    shllnzl Posts: 1,810 ✭✭✭✭✭

    @christinelevine Hi, welcome to the Grow Network.

    All of the above suggestions have merit. I have and will try most of them.

    I had a terrible infestation in my houseplants last year because of eggs in purchased potting soil. I used that soil to plant walking onions -- turns out that onions are the favorite food of the larva. If you're growing onions, check there first.

    I used a Bt based powder to water the plants with the intent to control the larva. Eventually that worked, although I killed a few plants through over watering. You can use the mosquito rings in your water jug or purchase powder that you can add to water.

    I still have YELLOW sticky traps located throughout the house to warn me if the gnats come back this spring. The vinegar/soap traps did not work for me. Interesting side note: BuggyBeds solid bedbug traps that I had bought for a possible hotel bed problem during travel also attract fungus gnats. I laid the trap on top of the soil and the gnats crawled into the traps.

    I had someone tell me that they got rid of the gnats by putting sand on top of their soil; I never tried that.

    Note that the gnats will feed inside your sink drains, so we closed our sink drains and taped off the overflow hole. The kitchen sink cannot be closed sufficiently, of course, so we used the sticky traps in that area.

    Good luck.

  • DurwardPless
    DurwardPless Posts: 162 ✭✭✭

    Good information for us "newbies".