My lawn is mostly clay soil. Have a few spots where grasss just refuses to grow. Tried digging up and replacing the clay w/new soil, applied organic manure, tried different types of grass seed. Need help as to what to do to the soil in order for the grass to come in and not die off.

The best remedy for improving clay soil is to add gypsum which breaks up the structure a little and allows better drainage. Clay soil is rich in nutrients, however if it is not properly aerated and/or overwatered, problems can occur with poor drainage and air starved grass roots.

Good aeration is vital for a healthy lawn. I would suggest that you thoroughly aerate the affected area with a garden fork and then add some gypsum and peatmoss to prevent the soil from closing in again.

Any new grass seed sown needs to be kept moist for the first couple of weeks, then water less frequently in order to establish strong root growth.

What ratio are you suggesting? Using cups as a measurement would I use 2 cups of gypsum to 1 cup of peat moss? Or the other way around? Have tried to aerate the lawn best as I can but will have to get those spikes you attach to your shoes to walk around you lawn and aerate it that way. Fork takes a long time as clay is very hard (like rock solid) soil.

My soil too is heavy clay. It has taken me a few years to get the soil anywhere near being able to grow grass. I have found that mid march is the best time to dig it up. I could actually get the shovel in about 8 to 10 inches to turn it up. I then added clay buster and peat moss to till in. after two years I can now dig the dirt down to 12 inches. It's a lot of work but that is all I have found. When you aerate you should use a plug aertor not spikes. Then rake in with organic materials. Hope this helps and I too feel your pain with this blessed soil.