Slab of concrete under lawn!
When I bought my house, there was an old shed in the backyard that I had torn down by a "professional". When the job was almost done, there was one slab of concrete left, and my dumpster had filled up for the upteenth time, so instead of paying to rent a new dumpster just for the last slab, we decided to cover it with dirt and let the grass grow on it. (I was poor and an idiot, I realize that now)
Today, as you probably expect, I can tell within an inch exactly where that slab is under my lawn. Every summer the grass on top dies and only weeds grow. The slab is about 10' x 10', and has about 6" of dirt on top.
I've never actually sodded my yard, over the years I've just added St. Aug runners and vigilantly weed & feed and I've got it to about 50% St. Aug and 50% weeds/bermuda/other junk.
WHY isn't grass growing here? It doesn't make sense, to me, that a cement slab under 6" of dirt would affect my grass, but it does. Is it drainage issues? Not getting nutrition? Something else?
Now, I would have assumed that 6" of dirt is enough for St Aug to grow on top of cement, but apparently it isn't. However, my theory is that I simply haven't tried hard enough. SO my first option is to till up this area, put down about an inch of good black dirt, then sod it with a good carpet of St. Aug and give it a chance to really take off and grow. Shouldn't that work?
My second option is to get some other sort of grass that may be more tolerant of this less than ideal condition and plant it instead. This is not my favorite option since I'd much rather a uniform lawn.
My third option is to maybe get my hammer drill and drill holes in this cement to drain water or something? This will take forever though since that slab is THICK and that hammer drill turns your arms into jello.
My last option is to finish the job. Get a 'dozer out there, dig up the slab, and get it disposed of. This is the best option of course, but it will be hard and expensive.