Photographs by Erin Boyle.
1. Allow the soil to dry out completely between waterings. Fungus gnats breed in the rich, dark soil of houseplants, and they’re especially happy if that soil has been zealously over-watered. Take a step or two back from the watering can and make sure you’re not creating exactly the kind of moist environment these little bugs love.
2. Be ruthless—and repot infected plants. If you discover that one of your plants is very badly infected, it might be worth sacrificing that plant for the sake of your collection. Fungus gnats can spread from one plant to another fairly quickly, so take caution. If the infestation isn’t so bad, consider repotting the plant. Remove the plant from its pot and use your fingers or a small brush to gently remove as much soil as possible from around its roots. Give the roots a quick rinse and repot in a clean pot with fresh, uninfected potting soil.
3. Bury a garlic clove in the infected soil. File this one under “What Can’t Garlic Do?” and give it a shot. According to the new edition of The Old Farmer’s Almanac, burying a clove of garlic in the soil of an infected houseplant will eradicate pests. What happens when the garlic begins to grow? Give it a trim.
4. Make your own sticky traps. Cover a yellow (or other brightly colored) card with a thin layer of honey. Attach the card to a toothpick and place in the surface of the plant soil. After the card begins to host tiny black insects, dispose of it and start fresh.
5. Make an apple cider vinegar trap. Pour fresh apple cider vinegar into a jar or bowl with a wide rim. Cover the bowl in plastic wrap and poke a series of small holes in the top of the plastic wrap. The gnats will be attracted to the sweet smell of the vinegar and will find a way into the bowl—but won’t be able to find their way out.