Growing Tip:
She Creation's Worm Casting Methodology
-- Cultivation of Marihuana Factoid

The mix that I recommend is basically nothing but castings and drainage. I used to cut it with all sorts of things, including soilless peat-based mixes like pro-mix.. but then you're introducing a source for pH problems-- especially when others try and duplicate it but can't find the right brands then substitute with a peat-mix that is too acidic. So down to the bare basics of a mix:

40% castings
30% perlite
30% vermiculite