I know for a fact that some people have chosen my company due to my education. I have a couple school teachers and I know that the education sealed the deal for them. Mind you, I dont cut grass 7 days a week. my company provides many services and mowing is a small piece of the pie. If I solely were mowing all day every day I definately wouldnt have went to college for it. I didnt learn a single thing about mowing or turfgrass in college. I had the choice of a turfgrass class or arborist class and chose the arborist class. I knew very little about plant material before I went to college and took a class in which I learned all about over 200 different species of plants. I went to school because I wanted to be a landscaper who also does lawn maintenance.
If your son is just going to run a mowing crew then I dont think it would be in his best interest to go to college for anything other then business, if he goes for anything.