If your lawn stays thirsty even though you water often, you might have a problem with thatch. Thatch is a brown, spongy material made of grass stems, living-, and dead grass roots that forms a mat along the surface of the soil. It resembles peat moss in look and feel.
Though thatch can be useful in small amounts to help keep the soil cool and the lawn comfortable to walk on, once it gets thicker than a half-inch, it turns into a big problem for lawns. Plant roots are lazy when it comes to penetrating a resistant soil, and most plant roots will remain in the easy-to-grow area created by thatch, instead of forcing their way into compacted soil.
Over time, the major part of the grass’ root system gets limited to the thatch layer, which doesn’t hold water or nutrients well. The result is turf roots drying out and top growth burning back despite excessive irrigation. Once this happens, the recommended amount of water will not be enough to keep your lawn healthy.
Thatch can be a problem on Kentucky bluegrass, bentgrass and fine fescue lawns, but rarely on tall fescue or buffalograss. To help slow thatch buildup core aerate each year to break it up and encourage roots to grow into the soil profile. But wait to aerate until fall or put it on your calendar for spring – mid-summer is not a good time to open up a bunch of holes in the soil for the heat to dry out.
Contrary to myth, grass clippings don’t add to thatch problems; use a mulching mower to leave the clippings on the lawn to recycle the nutrients they contain.