How to Remove Gnats From Potting Soil
Fungus gnats are insects which look like small mosquitoes and thrive in organic matter found in potting soil. Although they are merely an annoyance in their adult, flying stage, their larval stage can damage or destroy plant roots. Removing fungus gnats from potting soil takes persistence and requires interrupting the adult egg-laying cycle. Does this Spark an idea?
Other People Are Reading
Things You'll Need
- Mosquito control discs containing bT
- Potato
- Lemon oil or orange oil
- Cape sundew
- Sand
- Yellow stick insect tape or cards
- Insecticidal soap
- Imidicloprid insecticide
Instructions
-
-
1
Let potting soil dry out between waterings. According to the Colorado State University Extension Service, this is the single most important management technique for controlling fungus gnats in potting soil. Add a bacillus Thuringiensis (bT) mosquito control disc to the watering can when watering potted plants to kill
-
2
Kill larvae in potting soil with organic methods. Add a bacillus Thuringiensis (bT) mosquito control disc to the watering can when watering potted plants to kill off larvae as they hatch. Set thin slices of potatoes on the potting soil surface; remove and replace them every few hours along with the fungus gnat larvae that crawl out and cling to the underside.
-
-
3
Kill adult fungus gnats to preclude them from laying eggs back in your potting soil. Trap flying insects with sticky yellow insect tape or cards, or grow Cape sundew, an interesting-looking carnivorous plant, near your other houseplants to eat the adult fungus gnats.
-
4
Spread a half-inch layer of sterile sand on the surface of pots to make it difficult for adult fungus gnats to return to the potting soil. Rub lemon oil or orange oil around the edges of houseplant pots, or place small dishes of lemon juice around the plants. Spray the plants with a light mixture of insecticidal soap.
-
5
Houseplant insecticides containing the chemical imidacloprid will kill fungus gnat larvae in potting soil. This substance is often a component of household insecticide granules, and may be found in combination with pyrethrin-based insecticide sprays which are effective at killing adult fungus gnats. Repeat applications of insecticides every seven days to kill off any subsequent fungus gnat hatchings that may emerge from your potting soil.
-
1
Tips & Warnings
Some gardeners bake their potting soil to sterilize it. Baking may kill fungal gnats in a small quantity of potting soil, but will also destroy the good organic matter in the soil necessary for potted plant growth and health--and it makes your kitchen smell awful, so skip it.
Always use insecticides and other pesticides in accordance with manufacturer's labels, using adequate ventilation and washing your hands thoroughly afterward.
