OK, maybe I misunderstood. I was under the impression that the CT's contained mycorrhizae. These are nitrogen fixing bacteria, are they not? As far as the "mining" that happens, ALL of the essential nutrients need to be present to be mined, otherwise they need to be added in some form or fashion...again, in some practical way. Am I wrong? C'mon Smallaxe, You're not talking to some greenhorn rookie in the lawn business. I'm well aware that weed control is not some magical compound contained in NPK. I do know that when these are available in sufficient quantities the lawn is healthier and in most cases thicker because of this health. Nobody can argue that a thick lawn aids in weed control. Weed control and ferts may not be in the same discussion for you but to me they go hand in hand. My customers are looking for a healthy, hopefully green, WEED FREE lawn. In their minds, these are all tied together and are what I'm there for. If I ask them to lower their expectations because I've decided to do the "right" thing and "Go Green", I still need to be able to maintain pretty close to that level of expectation. Otherwise, like I said before, my customer list will surely dwindle.