We've bought soil from different sources, and granted our garden areas do not get full sun all day long; however, our summers have been very dry and hot. This year the wind is drying the soil even more now. So we water frequently. Problem is, while plants seem to like it, the soil has developed what I believe is mold: white throughout when I dig. Is this common? Harmful to plants? What do you recommend to get rid of it?
Is White Mildew/Mold in Soil Eventually Harmful to All Plants?
It's possible that what you have in your soil is mychorrizae fungus, a highly beneficial and desireable organism which breaks down organic nutrients for the plant roots to absorb. Mychorrizae is the key to successful bonsai, for instance, and forms a symbiotic relationship critical for potted pines to live in a closed environment. It is a distinctly filamentous (ie. "stringy"), substance which doesn't show above the surface but permeates the root area of the soil. If what you have is a surface organism, it is likely something else altogether. In any case, be it mildew or mold, it will not thrive unless the soil is damp and somewhat shaded.