Hi, I had some "premium" topsoil delivered in bulk from a local mulch company. We put in our raised beds about five days ago and when we went to turn it... a lot of the dirt underneath had turned an ashey looking gray color...is this some kind of mold? Should we be concerned about planting? We have had a lot of rain lately but the soil itself was covered when it was in our driveway before we added it to our bed. Thank you! Carol