Home Remedies to Kill Houseplant Gnats

Houseplant Gnats

• Houseplant gnats rarely infest a plant so seriously that they cause lasting harm. The main issue is their annoyance factor. They congregate around the infected plant, but also gather around light sources such as windows and light bulbs. You might find them in your kitchen or bathroom sink. Killing the flying adults will only solve the problem temporarily; a new generation of larvae will soon hatch out of your houseplant's soil and the infestation cycle will begin all over again. The home remedies you use to kill houseplant gnats must focus on both the adults and the larvae.

Cultural Changes

• Make your houseplants uninviting to the gnats. Let the soil get dry between watering. This stops adults from laying eggs in it and kill larvae already inside of it. Place moist chunks of potato on top of the soil. Wait two days, then pick them up. Larvae will abandon the dry dirt and burrow into the potato. Wrap the chunks in plastic and dispose of them outside. Pour an inch of sand on top of the houseplant's dirt. The adults cannot get to the soil to lay eggs, and the larvae can't burrow through it once they mature.

Other Controls

• If the plant is healthy, you can drown the larvae. Pick up the plant pot and put it into a larger bucket full of water. Leave it for a few seconds, then pull it out. The plant's dirt is flooded with water, killing the larvae and any adults on the dirt. Use an all purpose insect spray to kill the flying adults. Pour 1 tsp. of liquid dishwashing detergent into a spray bottle, then add 16 oz. water. Shake the mixture well before spraying it on the gnats. Dishwashing soap kills them. Wait five minutes, then wipe up the dead insects and any lingering water with a sponge or paper towel.

Considerations

• If these home remedies do not work within a few weeks, or if the plant begins to wilt, you have two choices: either discard the plant and its soil and start fresh with a new one, or purchase a biological insecticide soil drench intended specifically to kill fungus gnats and their larvae. While treating an infected plant, consider moving it outdoors. This prevents the gnats from infecting other houseplants in your home.