I have spots in my yard that the grass just won't grow. What do I to

Remove the dead grass,put a few inches of top soil,a gras seed for sun and shade,starter fertilizer,lime and top with peat moss.

From my experience St. Augustine grass is the way to go even in shade.

The reason it isn't growing is because the trees are causing too much shade. You will have to cut the trees back substantially to allow enough sun back to the area. For that size area after you remove the old grass and add top soil I would re-sod if you are going to do the work yourself. If the green is all grass and not part weeds you can sod around those areas but you will still need to add some topsoil to it.

check soil ph near the tree.....some trees will secrete a substance that will kill the grass. pine trees are noted for this, but other types do it as well. i put down a serious layer of wood chip for mulch, and let them degrade. i now have grass.

Cynthia- thanks for the picture most post fail in this area. We can see some of the problem. Shade is the killer here. Trim back you trees #1. Do you have dogs because urine will also kill your grass. #2. I would rototiller that area and add so fertilizer then plant new grass seed or use sod. Your local nursery ( Home Depot, Ace, Lowes, etc.)will be able to tell you the best grass to plant and the time of year.

We have the same issue, but you can get grasses that are formulated (genetically modified) for shady spots.