good question myco.i use my cement mixer. chuck a shit load of softly binded quartz and granite ,limestone.let mix for an hour this method works well.do wet and tip/ wash all dusty sludge out .then i add coir,soil,perlite and slow release ferts to mixer this ensures even distribution of all the parts.ideal for garden beds or a yearly spring re-pot great if you own a mixer or can borrow one. cheers flummy