If your going for soil bacteria count I'd say consider inoculation. There are ones you can buy but who wants to buy? I like to take soil from various places like the woods, organic gardens, and wherever seems good. I mix that soil into my gardens by simply throwing it about before or during sheet mulching. I'd imagine it could be mixed in a potting mix also. Hope that helps, I don't do many plants in pots yet, I mostly just try to concentrate "energy" by putting whatever I find as far as biomass together.