Have you ever noticed that layer of dead grass underneath the green layer of your yard? This dead grass is known as thatch, which is an accumulation of dead and living plant material that develops between the soil surface and the living grass. Many times a small layer of thatch is desirable. A small layer can help the soil retain moisture and keep weeds from germinating. However, if thatch exceeds

depth of ½ inch, then problems could occur.

If dead areas are starting to form in a yard, there are a number of reasons that could be at the root of the problem. The first cause that needs to be examined is thatch. Homeowners can examine thatch by using a knife, spade, or soil probe to remove a small section of turf (soil in- cluded). If the thatch layer is thicker than ½ inch, dethatching is needed. Thatch buildup is gradual and occurs over a period of time. Therefore, it’s logical that a thatch removal program should also be gradual.

The following are cultural practices that are effective methods of thatch removal.

Core Aeration

Core aeration is my favorite method of correcting a thatch problem. Core aeration benefits thatch decomposition primarily through the indirect effects that stimulate bacterial activity. Core aeration also relieves soil compaction and increases air and water movement into the soil. This is best accomplished by a power aerator that has hollow tines or spoons, so it removes a soil core 2 to 3 inches deep and 1/2 to 3/4 of an inch in diameter. Core aeration should be done during periods of active plant growth and when the soil is moist enough to allow deep penetration. Applying a fertilizer as recommended by soil analysis after a cultural practice will increase the rate of turf recovery.

Burning

Burning is a practice that is very easy to do and costs very little (as long as you don’t burn something else up!). In the winter, grass for the most part is dormant. If you dig deep enough, you may find some green stolons or green leaf tissue but the majority will be dormant. Burning destroys all layers of thatch, allowing no competition for the emerging grass in the spring. Again, just be careful with burning and always have a garden hose handy.

Topdressing Topdressing once or twice a year with a 1/4 inch layer of topsoil is the most effective method of thatch reduction. This practice increases the thatch decomposition rate. Heavier applications of topsoil may cause layering, which restricts water, air and fertilizer movement in the soil. However, a top-dressing is also the least practical cultural practice because of the cost of specialized equipment, top-soil, and labor. Topdressing can also be a source of weed seed.

As you can see, there are a few available options for dealing with thatch problems in a yard. As always, call the Extension Office with all your questions.

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