What is thatch and how to prevent it?

As part of a regular lawn care program, it is recommended to check your lawn for dense layers of roots and decaying plant matter which resides between the grass plant and the soil, also called thatch, which causes thinning and makes the lawn more susceptible to disease and weeds. While a normal layer of thatch will protect the crown of the grass plant and prevent soil compaction, heavy thatch buildup will prevent rain and fertilizers from penetrating the thatch layer. This robs your lawn of the water and nutrients needed to grow a thick and healthy turf.
Checking for thatch in your lawn

You can check for thatch by lifting a section of the lawn and measuring how much decaying matter there is and where the roots are in relation to the soil. One-fourth to ½-inch of thatch is considered about right.