Clear worms in potting soil

Asked March 29, 2018, 10:08 AM EDT

Recently, I found clear, tiny worms in my soil. I think they are fungus gnats and my soil was to wet. I had seeds planted, but they seem to have rotted and the soil stinks. Question is, can I reuse the soil and how?

Baltimore County Maryland soil pest insects and mites

3 Responses

It does sound like fungus gnats are a possibility. We would not recommend re-using the soil, as it may contain more fungus gnat eggs and larvae. Start with fresh soil or potting medium and let the surface dry between waterings. Fungus gnats are attracted to soil that is kept consistently moist. Here is additional information about these insects and how to manage them:


I baked the soil in the oven at 260 f for twenty minutes or so. Should be ok???

You may have gone a bit too high with the temperature. Here, from Colorado State University, is information on the heating of soil to control fungus gnats:

Oven Method - Spread soil not more than four inches deep in non-plastic containers, such as seed flats, clay pots, and glass or metal baking pans. Cover each container tightly with aluminum foil. Insert a meat or candy thermometer through the foil into the center of the soil. Set the oven between 180° and 200° F. Heat the soil to at least 180° F; keep at this temperature for 30 minutes. Do not allow the temperature to go above 200° F. High temperatures may produce plant toxins. After heating, cool, remove containers from the oven and leave aluminum foil in place until ready to use. The heated soil will give off an odor.

Or, get new potting soil. Use only sterilized container mixes for houseplants. Store any excess potting soil in closed containers. Adding a layer of coarse sand on the top of the soil can help to deter fungus gnats. Allow the soil surface to dry out between waterings.