I applied a weed killer several weeks ago and this has added to an area in my yard that is very sparse of grass. I applied milorganite in early spring but I am having difficulty getting grass to grow thick in certain areas. Would areating the yard, then applying a heavy top seeding over this help? Is there a type of areation that would work beter than others? Would you apply a fertilizer over this now? I am in Michigan and cool days will soon prevail. How deep does one areate? Any suggestions would be appreciated.