Why not keep it very simple and use premade potting soil? I know it might not be what you want but it will give you a good starting base and learn the plants that you grow in it and how they react to things. A $5 bag of Merical Grow potting soil will do the job. I have seen people spend more money then that 1 bag of potting soil cost and I have and the same plants as them and mine grew around the same maybe better then their more expensive soil.