If you pick up a good mix from any garden store, one that dosent have added fertilizer, then mix it 1/2 and 1/2 with perilite. After that I add a few soil amendments, kelp meal, greensand, cottonseed meal, worm castings. It's always changing to be honest, but when I make up the final mix it's about 80% of the perilite/soil mix and the other 20% is the soil amendments I use. MY personal mix is 40% peatmoss, 40% perilite, the soil amdendments vary in proportion but its about 10% kelp meal and worm castings and a dash of the other amendments. It takes about 4 tbl of lime per gallon of soil to keep it in the right pH range.