Your grass may not be alone. Underneath, there may be thatch lurking. But that may not be a bad thing. Thatch is the build up of old grass roots and rhizomes. Warm climate grasses such as zoysia, Bermuda and buffalo grasses can produce thatch at a reasonably fast rate and may need to be dethatched more often. Cool season grass, like our old friend, bluegrass, produce thatch more slowly. So let's not freak out about thatch. Thatch that's not too think can be helpful. It can keep soil cool, slow