advantages of perlite?
I'm in charge of a couple of small greenhouses housing several hundred diverse species. The tradition here has been to mix our own soil. We use a ratio of 1:1:1 of peat moss, sifted top soil, and perlite. (then we pasteurize it) I find that the perlite tends to work it's way to the top and is often rinsed away. Can anything be substituted for the perlite? I'm not happy with our mix at all - I think it dries out too quickly and with time compacts too much (and the perlite seems to have disappeared). I appreciate any advice! Thanks, Cassiope