Fungus Gnats: How to Get Rid of Them Organically
Photography by Marie Viljoen. Ah, the perks of an indoor garden in winter: Fruit, flowers, fragrance, and…fungus gnats? Worse, if you do see a lot of the tiny, winged varmints, it means that their even tinier but much hungrier larvae are living in your pots, eating organic matter that includes the roots of your plants, which they damage. If only cats would catch fungus gnats. Fungus gnats are a warning sign: They thrive in moist environments, and their presence indicates you might be overwatering your plants. Adult fungus gnats, trapped. Like scale insects indoors, they seem to materialize from the ether. The pros and cons of indoor growing—fruit, and pesky critter control. Step 1: Do not overwater. I water my plants when the meter reaches the red zone. Allowing your pots to dry between waterings helps prevent a fungus gnat infestation, and it also keep your plants healthier: Root rot is caused by overwatering and can be fatal. Forty-eight (cute) yellow sticky traps are $6.98 on Amazon. The traps effectively sequester the adult gnats, interrupting their relentless life cycle by preventing them from laying eggs in your soil. Step 2: Use yellow sticky traps. Fungus gnats are also attracted to dishes of soapy water. The fungus gnats are attracted to the water and drown thanks to the soap, which breaks the surface tension under their tiny legs. Step 3: Bacillus thuringiensis subsp. israelensis (Bti) BTI for fungus gnat elimination. When sticky traps alone did not get rid of fungus gnats... ...I turned to Reddit, which is where I learned about biological warfare. Because it does not persist in the soil, this is a long-term, repeat solution. Ripe yuzu in January, around peak fungus gnat season. While I have found no studies that indicate any attached risk to using this biological control, it is important to use common sense when deploying a living counter-measure.