I have approx 35,000 ft2 lawn that I am in the process of renovating. To make a long story short; I killed off the lawn with round up, had a contractor come in and remove most of the vegetation ( mainly weeds) and do a complete finish grade (with 15 tons of new topsoil) on front and back yard to resolve some drainage issues we had. We also installed an irrigation system in front yard. I seeded everything with Lesco transition blend seed (tall fescue). In the back yard I put down a "dusting" of peat moss to help keep the soil moist. The irrigation system in front yard is keeping the soil moist. 3-1/2 weeks after seeding now and almost about ready to mow (the starter fert. from lesco must be powerful stuff). The new topsoil was mainly for front yard, the back was re-graded for better drainage. The back yard has a-lot of clay, so much so that it is already hard as a rock three weeks after it was tilled and graded. I know I need to get some organic mater in the clay soil. My question is how is best to do this? I've seen posts about using compost at 1 yard per 1k, but in may case that would be 20 yards worth of mulch ( back yard is approx 20,000 ft2). I hate to seem lazy, but I am not going to move that much compost with a shovel and wheel barrow. Will the use or organic fertilizers add organic matter to the soil? Obviously they will take time to get as much OM as 20 yards of compost, but a little easier on the back too. I'd like to have something that could go through my rotary spreader. What is the best product for me to use?