i actually saw someone on another site post a link for home depot, and they carried promix, but of course when i checked my local hd but putting in my zip, none of the ones around me carry it..
but i'm sure that you can find something decent there.. just read the package, and make sure that there are no time released nutes or anything like that.. i actually picked up some soil there before called jiffy mix i do believe.. it was only a small bag and it was near the jiffy pellets in the store.. its used for seedlings and clones, and i liked it a lot.. was pretty nice, and i didn't have any issues with it..
but yah, just look for some thing that contains no added nutes to it, maybe look for something that may say organic on it.. i think that the jiffy mix says organic on it if i remember right..