Thatch occurs when plant material builds up on the surface of your lawn. While some thatch is a good thing, too much will eventually kill your lawn by starving it of oxygen and nutrients. If your lawn is brown underneath a green surface--or if it looks dead when you mow--you may need to thatch. If you have a small lawn or need to thatch only a small area of grass, then your best bet is to use a thatch rake, sometimes referred to as a "dethatching" rake.
Things You'll Need
Remove a small plug of your lawn. Measure the layer of thatch. A small layer, less than 1/2-inch, is good for your lawn. It will help moderate water levels and the surface temperature of your lawn while keeping down weeds. More than 1/2-inch of thatch will restrict the air movement; that can literally suffocate it and lead to problems with fungus and bacteria.
Mow your lawn so the grass is approximately 1-inch high. This will make it easier to thatch.
Hold the thatch rake at an angle so the tines just cut into the soil.
Pull the rake toward you. Push it away to remove the thatch. However, some suggest that you should only use the thatch rake in one direction, or you will risk damaging the roots.
Rake up any thatch or debris with a leaf rake. Remove it from your lawn.
Reseed and fertilize your lawn, if desired.
You only need to dethatch your lawn ever two or three years. Dethatch cool-season lawns in the early fall or spring. Dethatch warm-season laws in the early summer.
Your lawn will look worse after you use your thatch rake. That is normal, and it will look better in a few weeks. Do not dethatch your lawn in the middle of the summer.