I have been mowing a couple of years now but I am still pretty much a rookie. I was wondering what it is about this time of year that when I mow grass the discharge is brown and I leave rows of brown. I have one yard that is heavily fertilized and its difficult to get it to look good after one week of growth. The brown discharge rows show up pretty bad. Most of my lawns grow at a more moderate pace and this is not a problem. I can go back over it and get it to looking better. Is this the build up of grass over the growing season ? Is this why they dethach lawns? I know this sounds like dumb questions to more seasoned lawn care proffessionals. I mow with a lazer z with high lift or gator blades this time of year. Thanks!!!!