I have large bald spots in my back yard which I was told was created by clay soil and rock bed under the lawn. Should I use Leaf Grow or Manure with Humus to repair the bald spots?
Baltimore County Maryland
Leaf-gro and the others you mention are all good organic amendments, which can help enrich and loosen the soil. You may want to try and loosen the ground a bit mechanically too by using a garden fork at intervals and maybe even a shovel to remove what rock you can. Grass roots need room to establish.
Here is our lawn page with many helpful links to get the job done: http://www.extension.umd.edu/hgic/plants/lawns