Long story, When we moved in 20 years ago, my wife I cleared the backyard and I labored for years to get a good healthy lawn. I finally got it to be ok, and then about 5 years ago strange things started to happen like large patches of the pachysandra surrounding the lawn died off suddenly, and nothing kills that stuff. About the same time good grass died out too and was taken over by some invasive grass which goes completely dead in the winter. I fought it trying to patch spots and that was worthless. Then I rented a tiller and tilled the whole fooking thing, adding top soil and fertilizer before reseeding it. The new seed grew nicely for about 6-8 weeks but be the end of the summer was dead again. I suspect there is some kind of fungus effecting the whole backyard but I tried antifungal and it didn’t do anything. I’ve spoken to a few landscapers and they couldn’t come up with anything. That was 3 years ago and I haven’t had the heart to tackle the project again not knowing if it would work.