We’re just going to say it: fungus gnats are a nuisance, especially on houseplants. These small flies can infest your indoor plant’s potting mix, feeding (and thriving) off the fungi and organic matter in the soil. Left untreated, they’ll eventually chew on the rotting roots of your plant – in other words, you want to take action as soon as you can.
If you’ve noticed dark, tiny flies hovering near your houseplants (or light sources), we recommend by starting here:
Soil and Water Management
First, always check your indoor plant’s soil. Overwatering is a common culprit as it creates the sort of poor drainage conditions fungus gnats thrive in. To avoid, it’s as simple as ensuring good drainage with consistent water. Allow the surface of your container to dry out between waterings and wash the saucer of any standing water. We recommend only using pasteurized container mixes when repotting your indoor plants.
Methods to Eliminate Fungus Gnats
Fortunately, it’s best to go the natural route here. If you have flies, start by removing the top inch of potting soil from your plant and replace it with new, sterile (aka fly free) container soil. This is an important step because the fungus gnats have laid eggs and larvae in this top layer of soil and you don’t only want to get rid of the ones you see, but the ones to come. Dispose of soil in a sealed container and place it in the trash. If you want to further deter gnats from laying eggs, try topping your soil with gravel, decorative moss, or even sand.
As an insurance policy for the future, try adding an organic insecticidal soap and water mix, or neem oil mix, to your new top soil (where gnats usually lay their eggs). This will help with a variety of pests and is fine to reapply every 7 – 14 days.
Featured image source: https://www.flickr.com/photos/andybadger/6917082337