I mix my own soils using perlite, vermiculite, peat moss, potting soil, kitty litter, mushroom compost, chicken manure compost, cow manure compost and cotton compost. I amend that with lime, Epson salts, blood meal, bone meal, coffee grounds, organic fertilizers, bulk farm fertilizers and time release fertilizers. So far no two mixes has been exactly the same, but 2 five gallon buckets of peat moss and 1 each of the potting soil, kitty litter and the composts is kind of a baseline. Then 12 cups coffee grounds, 4 cups lime, 1 cup Epson salts, 1 cup vermiculite, 4 cups perlite {more if planting into heavy clay soils}, 1 cup blood meal, 2 cups bone meal and 4 cups each of four organic {3-3-3 and similar} fertilizers. The next part is determined by how much of the mix I'll be using per plant. {ie... how far will I have to carry it} For the long walk plants, I mix it really hot, and use a third of a bucket per plant. For close by plants,they might get 2-3 buckets each. So for an average mix, I add 1 cup 15-0-15, 2 cups 13-13-13, 2 cups 10-10-10, 4 cups 6-6-6, 4 cups 13-7-13 time release and 4 cups 19-6-12 time release.