I respect your views on lawn maintenance and will not discourage you treating your lawn in any way you prefer, but to throw out the "don't use any of those products because they contain chemicals" is a bit much. The products listed do not damage lawns unless grossly over-applied against manufacturer suggested rates. If another person chooses to treat their lawn with proven products, that's their business. You're entitled to your opinion as they are their own. I'll say that I wouldn't waste my time with nematodes on my lawn, but that's just me. I don't have a ton of time to mess around in the lawn, and I'd rather see results sooner. I have access to all sorts of lawn care products since I sell them, so that's the route I take with my lawn, but I'm not disparaging the way you take care of yours.