St. Augustine grass dying- Please help
My grass has been slowly dying over the last year. I tested the PH Levels and it's fine at about 6.5. I have no idea what's been causing it. A couple of months ago I added steer manure, all-purpose fertilizer, new grass plugs, but it didn't take. I've checked for chinch bugs but can't find any.
The only other thing that I guess it could be is that it's too shady? I'm not planting anything right now because it's winter and it gets practically no sun. But in the summer it does get a good amount of sun..
The grass is in between 2 structures, and there's a tall tree that;s right outside the yard that also causes shade.
Please let me know your thoughts on what it might be. I know the drainage isn't very good, as some parts of the soil would stay wet on one side of the yard. But it was all working out fine 2 years ago, the grass was fine. I also plant winter rye grass and it takes fine for the winter season.