control the PH with Dolomite lime it also contains magnesium and is very gentle- worm castings tend to be a bit acidic also but the dolomite 1/4-1/3 cup for 5 gal mix will fix that as for the mix worm castings should make up about 20-25% of the total or it will compact too much. I use bat guano the kind w/o any nitrogen 0-15-2 when the plants are budding 1/4 cup per plant (on top of soil so water filters thru) every 2 weeks until the bud is 1 week from harvest then flush til u chop em good luck- organics rock!