Potting soil fungus/mold

Asked May 29, 2020, 10:12 AM EDT

I am trying to get rid of this growth in the potting soil of my window boxes by scooping it out and using fungalcide spray, but to no avail, it keeps coming back. Does it endanger the health of my plant and how do I get rid of it? Many thanks.

Montgomery County Maryland

1 Response

We can't positively identify this growth, but it could be a slime mold. Despite being called "molds," they are not fungi and likely won't respond to a fungicide. (A fungicide might inhibit beneficial fungi in the soil that aid plant roots, so avoid using them unless necessary and with a proper fungus ID.) Slime molds do not harm the soil or plants, and tend to disappear once conditions change. As the weather becomes drier and we move into summer, it will probably stop coming back. Allowing the surface of the potting soil to dry a bit between waterings (which is beneficial for the plants as well) may help.

Miri