Do You Have Soil Or Dirt???
We like to make a distinction between "dirt" and "soil". If you are growing plants in material that has no life, has little fertility and does little to support healthy plant growth, then we say you are growing plants in "dirt". If you have a medium that has sufficient air, water, minerals and microbial life to insure healthy plant growth, you have "soil". So are you growing grass in dirt or in soil? If you have dirt, you may need to take some steps to make it soil.
You do not have to be a soil scientist to figure out whether your lawn’s soil needs some renovation. All you need to do is answer a few fairly simple questions. Is your soil compacted? Does it have sufficient organic material in the top twelve inches? Does it have a full population of microbes and other creatures found in healthy soil that is alive with life. In this file we suggest some easy tests to help you answer those questions. You don't have to use all the tests. If two or three tests indicate that your soil is definitely in the “dirt” category, then don't waste your time with more tests; you need to fix the problem.
See the file “Caring For Soil Under Turfgrass” for advice about how to create healthy soil. Also check out Adding Organic Material To The Lawn.