I use alot of brown sphagnum peat moss, a large bag of Schultz potting mix, and a bag of cheap potting soil (screened to get rid of the chunky stuff) to make up enough for 30 to 40 gallons of a final mix, which I mix on a cement floor using a shovel and store in large garbage cans. To this base which provides humates, an acidic hit, trace elements, etc. and a little silt to tighten up the mix and retain moisture, I add:
6 or so cups blood meal, 3 or so cups bonemeal, 4 cups dolomite lime, 1 large bag each of vermiculite and perlite (available at Casa dePOT) and alfalfa meal which contains a hormone called triacontanol (purported to increase vegetable production up to 60%). I buy alfalfa feed pellets from a farm and ranch supply store, put about 4 cups of the pellets in a bucket with a gallon of water and give it a good squirt of Ivory dish soap to cut the surface tension, let it stand for 30 minutes, and then dump the slurry into the mix on the floor. I sometimes add composted horse manure, maybe about 3 or 4 gallons of it. The final, slightly moist soil mix is turned well with a shovel and stored for a couple of weeks in garbage cans to "mellow".