I always made my own potting mixes from scratch when I lived in the country and had a source of good forest humus, which I added to sharp sand and ground pumice. Now I don't have a forest handy (though I still, unhappily, own the forest, etc.). However, nearby is the "Indoor Garden Depot" which caters, I imagine, to indoor growers of something other than Rex begonias. They carry more than a dozem different kinds of potting soil, and I looked at all the ingredient lists until I found one that had none of the ingredients I dislike (Perlite and bark, in particular). I bought some bags of it and mixed it 2:1 with ground pumice, and it makes a good soil for both seeds and older plants. If you don't mind getting on some kind of DEA (Drug Enforcement Agency) watch list, you should check out these kinds of stores. They have lots of supplies and gadgets that any gardener would need, and an orientation toward organic growing. My neighborhood one has recently branched out into selling native plants, too. Sorry about the pumice; I know our mentioning it makes those in non-volcanic regions unhappy. Jane McGary Portland, Oregon, USA