I have a new customer with a lawn that is about a year and a half or two yearsn old. It was sod when installed. He said that he had a lot of yellow grass lastyear. He wants me to either dethatch it or aerate however I am not sure which would be best to do on a younger lawn. I would rather aerate because I am more familiar with doing it. The lawn is pretty thick also. Any help would be much appreciated.