Fungus gnats are tiny black flying bugs in houseplant soil. You'll see them crawling around on top of the soil, or flying around your plants.
No, fungus gnats will not kill your houseplants. They are mainly just a nuisance and are rarely destructive to the plant.
Fungus gnat larvae thrive in moist soil, and they can’t survive in dry soil.
Bottom watering plants will make it easier to maintain dryer top soil, without risking the overall health of the plant.
Putting a yellow sticky trap near the plant is a super safe pest control method that will attract and capture the adult fungus gnats.
Pour or spray an organic insecticidal soap or a neem oil mixture into the top of the soil to kill gnats in potted plants.
Remove the top inch of potting soil and replace it with fresh sterile soil. This will remove fungus gnat eggs and larvae, and make it easier to gain the upper hand.
Replace the top inch of soil with a layer of fine sand, gravel, crushed granite, or decorative moss. This will help control gnats in soil, and deter them from laying eggs. Plus, they also add a nice decorative touch.
Open potting soil bags can also be a breeding ground for fungus gnats, so make sure you keep that in mind when storing unused soil.
I know it’s tempting to pinch pennies by reusing potting soil for indoor plants, but you’re just asking for trouble. Always use a fresh, sterile soil mix when repotting your plants.