I used the GardenPro, as it too was the only one I could find without fertilizer built in. I would say I used 50% GardenPro, 25% vermiculite or perlite depending upon what I had on hand, 25% spag. moss. Topped the pots off with pine bark mulch. Fertilizer was osmocote, and I did treat a few plants with epsom salt water for what I thought was a magnesium deficiency (misted the leaves, and their color perked right up & has stayed that way ever since). I have a few that are in MG soil with the same perlite/vermiculite/sp moss ratio, and they appear to be growing at the same rate. I found the GardenPro at Meijer and WalMart in my area.