That’s a good question Daniel,     One I’m still working on.   im Using organic 2yr cow compost from local farmer and I add any veggies kitchen scraps to the bin.    Next spring I should have enough knowledge from a little reading I’ve been doing for awhile.  My plan is .....   I’m already have my own bins. (4)  20 gallon totes to grow my own above ground worms....  for the castings.   I don’t really like worms but find this may be  a worthwhile endeavor for my OD grows only.   For inside I use FF happy frog.            I’d love to hear from anyone on WP doing super soil.     And I want a Bat house way out back for a little collection too.