Frankenberry wrote:

I have a small lawn that is shaded on one end. Since I have owned the house
the shaded part was mostly dirt.

I dug up and turned the soil over and layed sod in this area. I also turned
over the soil and planted shady grass seed in the area between the existing
grass and the new sod. I also patched up areas one the grassy side to fill
it in. Within a week or so the grass and sod looked beautiful almost golf
course like.

But now 3 weeks-4 weeks later all the new areas have thinned quite a bit
(sod, patches, seeded areas). The original grassy area looks the same.

I tried fertilizing the lawn 4-5 days ago and so far no difference, everyday
the lawn looks worse. More dirt less grass.

I have watered it quite a bit and it has rained quite a bit too.

Does anyone have any sugestions why this might be happening and how to fix
it?

Also no one has been on the grass as its a fairly unused lawn.

Shady mix grasses need some minimum amount of sun each day - depending
on the variety. If the grass is in dense, full shade the entire day, it
likely will die. If shade is such that you can trim/lift trees to bring
more light it may improve the situation. If not, then a different
ground cover may work much better. Under trees, the ground can dry
faster because the trees take up a lot of water. When you water, do you
water deep or just surface? There can be pests involved, such as fungus
or grubs, but you can't diagnose those on the internet. Try taking a
couple of plugs of grass from the problem area, along with a scoop of
soil from 4-5 spots to your county extension service if they do soil
testing. They should be able to tell you whether the soil is the
problem. No sun = no grass. All grass has to have some sun.