I planted a new lawn on my 1+ acre yard last July. I used a mix of annual rye, perenial rye, fescus and bluegrass. The grass came in very thick, I had to cut it all they way til thanksgiving and I live in Wisconsin. Over the winter the annual died and the lawn is much thinner than last year. It also is taking longer to green up than the neighbors that have had there grass in for a year longer than mine. My questions are: should I use a pre-emergent crabgrass killer with a fertilizer or is the grass too fragile. If not what should I use as a fertilizer? Will the perenial rye, fescue and bluegrass spread and thicken or will I need to overseed? Thanks for your help.