For the last couple of years I have used miracle grow mixed with mini pine bark nuggets.
No complaints it works. A friend of mine who studies plant diseases for auburn univ suggested
A lower cost but effective potting soil. Simply take soil conditioner mix in some larger mini nuggets and a bag of compost & manure. You will probably need to add some fertilizer whether it be organic or not.
I will let u know how well it works. I planted broccoli and cauliflower in the miracle grow, and the brussel sprouts, kale, lettuce and a couple of herbs ( oregano & Rosemary) in the other mixture.