One problem with my backyard was a rather large patch of grass that did not grow so well. This was mainly due to it having been flagstone prior to being seeded with new grass. The problem is there was about four inches of sand and the grading let water pool up on the patio.
I tried to pull up some of the soil, but quickly realized it would take me a long time to pull up that much earth and I wouldn’t know where to put it all. I called a guy I have used for landscaping and he quoted me a lot less than I thought so I had them do regrade.
I followed this up with a layer of dirt, grass seed, peat moss, and straw. I diligently watered it until the grass was long and healthy.