Lots of suggestions for growing medium. I don't see Vermiculite in anyone -elses- medium. Is there a reason for that? My medium is 50% commercial potting mix (usually Miracle Grow), 10% coarse sand, 10% vermiculite, 10% chicken gravel, 10% perlite, 5% coir, 5% compost. I'll typically add extra vermiculite to the top inch or so if sowing seeds, and use vermiculite to cover most seeds. I add some extra sand in the case of plants that require extra good drainage. Randy R