Got some mud you'd like to link on the sidebar? Chuck it in here.

For all the time I spend looking at various techniques and growing tips, I know shockingly little about soil, especially when you buy it at a garden center. Lemmy has treated me quite well every time I've asked for gardening advice, so once again I come to all of you to ask: What exactly differentiates potting mix and in-ground soil? What should I be looking for when purchasing soil? Is the type I choose all that important? Enlighten me soil scientists, and add any other fun tidbits you think I should know.