Focus on the "humus" portion over anything else. Compost and vermicompost are what makes this deal work; generally speaking the higher quality the humus portion, the higher quality the soil. Kelp, neem seed (big deal imo) and crab shell are all I use for nutritional amendments in my soil, though I do utilize free herbs and plant material for compost and vermicompost as well as using oyster shell flour to "lime" the peat to prevent long term acidic fluctuation from it decomposing. Rock dust (micronized crushed rock the consistency of flour) is applied as a long term source of micronutrients (kelp helps big time here) and as a physical aggregate small enough for the fungal hyphae to latch onto and help expansion. I just bought a 50 lb sack of kelp meal for $52.50 out the door...lol, sorry I know it doesnt help but you should try looking around a bit more. Horse feed stores SHOULD carry this material, it's very valuable outside of gardening as well as for it. If all else fails heres where I originally sourced my kelp and crab shell from http://www.countrysideorganics.com/product.php?productid=89&cat=0&page=1 http://www.countrysideorganics.com/product.php?productid=116&cat=27&page=1 No need to compost soil, either recycle it into a new batch of peat and additional compost (if necessary), reamend lightly and cycle it again or keep the pots rolling along no till style. Meaning you don't disturb the soil outside of the initial transplant of the clone/rooted plant. There are plenty of people using the same exact soil in the same exact pot for years on end, with minimal inputs over that time.