You are probably seeing some penicillium mold on the pot. CowPots are basically sanitized during the manufacturing process, so they are free of mold spores, bacteria, etc. But, being a very fertile, organism free environment allows for some potential for opportunistic infestation, once the conditions are right, of the naturally occurring molds and bacteria that are normally in the air. It is probably nothing serious, but to be careful, you could use a small fan to improve airflow around the pots, allow for additional drying time in between waterings, or a chemical solution, if you must. I like diluted baking soda and soap mixture (1% baking soda in water and a few drops of Dawn or horticultural oil to make the solution sticky) as a general purpose fungicide spray. It works pretty well on most visible fungal infestations.

Thank you! I did notice that it eased up as the pots dried. I tend to be an over-waterer. I'll def try the solution if I see it again.

If it occurs only around the edges of the pots it might simply be inflorescence, a buildup of minerals from evaporating water. It's impossible to know without seeing it.

Jim

Hi Jim. If it happens again, I will certainly get a pic to get some feedback. Thanks!