My take on earthworm rich soil is that it likely means it is teaming with beneficial organisms and nutrients but it can also be teaming with bugs that like to feast on plants. Store bought soil can have bugs too though. If you use the outdoor soil, maybe be prepared with a good organic bug killer. @SubmarineGirl
had some product that she used with great results. I think @boo
tried it too and had excellent results. I think the company(the name escapes me though) has a free sample they will send out.