I have a lawncare business (solo) and as im growing larger, more and more of my customers are asking whether i do fertilizing. I am to the point that i want to get licensed, but i dont have a clue of this end of the business. I know nothing about fertilizers. When do you put on this fertilizer, when do you put on that fertilizer, what kind of fertilzer to use??? It seems really confusing, and intimidating to me. Is there a site that explains it in simple terms? Something like "fertlizing for dummies"