Over the seasons, clippings and pieces of dead grass accumulate in a layer just above the soil, this is called thatch. Too much thatch is unable to decompose in a natural process that forms a barrier, keeping moisture and air movement from the base of the lawn. If there is more than a half in on thatch buildup in your lawn it’s time to find a solution. There is a 2 way to remove the thatch and promote air and water circulation: Aerating and dethatching. Dethatching is performed through a power rake that combs your grass and removes large amounts of dead debris that was hanging on the top of the soil.