I am an Arborist by profession, but my buddy's new house has some turf issues. The grass is patchy! I figured that we could overseed his lawn with a slit seeder. My questions are: Does the lawn need to be rolled after overseeding? What is a good starter fert. or will it burn the new grass? When is a good time to overseed (maybe now late winter)? Thanks in Advance, Any tree questions are welcome in repayment for your wealth of knowledge.