Why Does My House Plant Have Gnats in It?

The gnats flying around your houseplant are harmful, as are their young.

You've got house plants. Everything appears normal, except you've seen a tiny insect or two flying around one of them. These are fungus gnats, and if left unchecked, they can damage your house plants.

Signs of Fungus Gnats

The first signs of house plant gnats will be a few tiny bugs flying around, then you'll see them roaming the soil surface. If they've been around for a while, you'll notice larger numbers of them. Your plant will begin to lose leaves and look unhealthy.

Where Did They Come From?

The soil your plant came in was likely infected with fungus gnat maggots. These maggots thrive in damp soil. Gnats that originated in one plant can lay eggs in another plant's soil.

How Do They Harm Plants?

Fungus gnat maggots feed on the small roots of your plant. The flying gnats are harmful because they lay eggs in plant soil.

How to Get Rid of Gnats

Insecticide spray will kill adult fungus gnats. Isolate the plant and allow the soil to dry out---this will control maggots, according to the University of Kentucky College of Agriculture. Remove the plant from the existing soil and re-pot in fresh potting soil. The University of Minnesota Extension suggests cleaning the pot with boiling water to destroy any remaining eggs.

Gnat Prevention

Allow potting soil to dry a little between watering. Use only clean pots for planting. When you bring a new plant home, isolate it from your other house plants for 30 days.

References

• University of Kentucky College of Agriculture
• University of Minnesota Extension