sebrightlover said:
ah ha! Thanks for the tips!
Would it be the same for an area that has died because of dog urine? Or would you need to add other amendments?
Nope, dog urine is a different problem altogether. The grass has died because of nutrient (mainly N) overload and sometimes a pH problem as well, both caused by being excessively peed upon. Of course it pretty much never hurts to do what you can to improve the soil structure (and the better the soil structure is, the healthier the grass, and the better it can 'take a joke'). But the dreaded "dog lawn-spot disease"

is easily curable by the following simple steps:
1) Prevent the dog(s) from peeing there in future (!). Seriously!
2) If the dog(s) do pee on the lawn occasionally, flushing the area with water after they pee (assuming you live in an area where water is plentiful enough to 'waste' for this!) will help sluice the pee down through the soil as well as diluting it over a larger area. There are commercial products, too, that claim to mitigate pee spot problems if sprayed on or fed to the dog... I know nothing whatsoever about them, though.
3) Wait a season or two to see if the grass grows back on its own -- if it is casual rather than chronic damage it most likely will come back without your having to lift a finger (although raking, very light mulching and an occasional watering during a dry spell would expedite the process if you're looking for something to do).
4) If the dogs have been *really* peeing like heck, or if it's gone on for a long time, and you find that the grass won't come back on its own, rake the heck outta the area with a bow rake or something similar, to loosen up the top few inches of soil; sprinkle 'a little' limestone unless you are pretty sure pH is not a problem; and reseed the same way you'd do for any bare spot. (Reseed in a reasonable season for your area, with an appropriate non-low-end seed mix, keep properly watered, and keep traffic off the spot until the new grass is very
well established).
You shouldn't have to actually replace any soil, since nitrogen does not stay resident in the soil for very long at all, although if you can't get seed to 'take' I suppose that'd be something to look into. I haven't actually seen that happen myself, though.
Good luck,
Pat