Today's advice, contrary to what was recommended in the past, is to leave clippings on the lawn. The old belief that clippings contribute to thatch buildup has been proved false.

Thatch is a buildup of old roots and stems, not grass blades. Leaving clippings where they fall not only saves the labor of collecting and composting them, but it also reduces the need to add fertilizer because the clippings themselves add nitrogen to the soil as they decompose.

Clippings also act as a light mulch that helps to conserve soil moisture. However, there are exceptions to this advice. If you have neglected your mowing or must mow in wet conditions, the long clippings are likely to form heavy, soggy clumps. In such cases, remove the clippings so that they do not smother the grass plants beneath them.

Today's new mulching mowers, also called recycling mowers, make it easy to leave clippings where they fall. The deck and blade designs allow these mowers to cut each grass blade several times, producing a finely chopped clipping.

Courtesy Yardcare.com