Just about all indoor gardeners have experienced this.
You're showing off your fabulous indoor garden to guests, and they appear! Annoying little flies buzzing around in everyone's faces! Many people think they're fruit flies, but they're actually fungus gnats. The act just as annoying as fruit flies, though. And they're definitely not something you want in your indoor garden.
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So what to do about them? First of all, it's a good idea to find out exactly what they are.
About Fungus Gnats
Fungus gnats (Orfelia and Bradysia species) look like delicate flies and can even resemble mosquitoes. The adults have slender legs and antenna that are longer than their heads. They don't bite and aren't really strong fliers like the housefly. They are attracted to light, so you may see them flying around windows or plants growing under full-spectrum lighting. You'll also see them crawling around on top of soil.
Fungus gnats feed on organic materials, including potting soil. They also breed and then lay eggs in the top 6-8 inches of soil. The eggs hatch into more fungus gnats, and the cycle continues. Once in the adult stage, the gnats are just annoying. But their larvae will feed on plant roots.
How to Control Fungus Gnats
The good news is that fungus gnats aren't that hard to control in your indoor garden. It's a matter of breaking the "birthing" cycle. Here are some tips, including this great graphic from the folks at Turbo Tenant. This graphic shows you a totally non-toxic way of controllling fruit flies that works just as well for fungus gnats.
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(Turbo Tenant/More great natural bug repellent solutions for indoors here: https://www.turbotenant.com/blog/natural-bug-repellent)
Other Tips for Stopping the Fungus Gnat Cycle
- Use yellow sticky traps to lure the adults. They stick and die, which stops them from laying eggs in the soil. This can be used in conjunction with the Apple Cider vinegar lure.
- Water properly. Fungus gnats thrive in wet soil. Let the top 6-8 inches of soil dry out, which will kill the larvae and stop the cycle. This can be done in most houseplants, except for those that require consistently moist conditions, like maidenhair fern.
- Ensure that the plant isn't sitting in water. If the bottom of the plant pot is consistently wet, fungus gnats will thrive.
While I'm at it, here's a great graphic on controlling annoying common houseflies indoors. Find tips for naturally controlling a bunch of indoor pests at this link.
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Clik here to view.
(Turbo Tenant/More great natural bug repellent solutions for indoors here: https://www.turbotenant.com/blog/natural-bug-repellent)