There are some other things you can add to improve your soil. I had a horticulturist/botonist out last year to take down some large trees that had died during our drought. He recommended adding 50lbs each of cotton seed and alfafa pellets and 10lbs of molasses per 1000 sq ft of soil every year in the fall. Then every 3-5 years add 50lbs of lime or 1000 sq ft of soil. We just poured it all on top of our yards and garden and left it there over the fall/winter. In spring everything was tilled under in the garden area along with my compost. It really made a difference. My garden grew great and my grass actually took this year (had to start from seed).