Then the grass plants are weakened, becoming more susceptible to disease and the stress of heat and drought. Leave the grass clippings when you mow. Since clippings are 80 percent to 85 percent water, they decompose rapidly and provide additional nitrogen for your lawn. Studies show that as clippings break down, they return 20 percent or more of their nitrogen content to the soil. A mulching mower will give you a cleaner look, as the machine blades finely chop the grass.
Small pieces break down, or decompose, more rapidly, too.
Think of all the plastic bags you will save by not bagging clippings, and most important, how you'll avoid contributing to our overflowing landfills. If you are unable to mow one week and the grass gets too long, either mow it twice to chop the clippings more finely or catch the grass in a bag and use it in your compost pile. Grass clippings do not contribute to thatch buildup unless you frequently leave long clippings on the lawn. Thatch mostly consists of stolons and other grass parts that are breaking down too slowly. A thick layer of thatch keeps water from reaching roots, and it can harbor pests.