I mix my own soil:
1 part Worm Castings
1 part Sphagnum peat moss
1 part pumice / lava rock / perlite / rice hulls / basically any sort of aeration you can get
After you get equal parts of those in a pile, add some BuildASoil: Craft Blend to the mix. I go 2 cups for every cubic foot(7.5 gallons). I also mix in some BuildABloom, since phosphorus helps with root growth and potassium helps in every stage of development.
Mix well, of course. You don't want any nutrient pockets or clumps of peat moss.
Then, let it sit for a week and put it in your pots. After that, add a handful of worms to each pot. Yes, i said worms. They help break down nutrients that take a while to become taken in by the plants.
I'm starting to try out cover crops, since i think it's something i've been missing so far.