April 14, 2004 | By: Ellen Brightwell

Mowing grass is a big enough task by itself. So is it really necessary to have to remove the clippings, too?

A resounding “no” is the answer from A.J. Powell Jr., Extension turf specialist with the University of Kentucky College of Agriculture.

“There are few if any good reasons to ever bag clippings after mowing cool-season grasses such as tall fescue and Kentucky bluegrass,” he said.  “It’s better to leave clippings because they add valuable nutrients to the lawn.  People can skip one fertilizer application a year by leaving clippings that provide an organic fertilizer.”

Another reason not to bag clippings is that it increases landfill use and costs. Grass clippings have minimal use around the home as a compost pile or mulch for vegetable or bedding plants, according to Powell.

“Because clippings are so wet when collected, they can keep a compost pile from disintegrating and make it have a bad odor,” he said. “Clippings are not desirable mulch, either, because you must be sure the lawn hasn’t been sprayed with a broadleaf herbicide in the past three weeks or so, and hope you don’t spread crabgrass or dandelion seed into the vegetable or flower gardens.”

Powell also dispelled some myths about clippings being harmful to lawns and other lawn-care misconceptions.

“Clippings do not add to a problem with thatch, a tightly intermingled organic layer of grass roots and stems that forms on the soil surface,” he said.  “Actually, a little thatch or surface organic debris helps moderate the soil temperature and retains some moisture. It also makes the lawn more ‘cushiony’.”

Clippings normally do not increase disease problems when the lawn is properly mowed by removing no more than one-third to one-half of the grass growth at a time.  When grass is correctly mowed, clippings will be evenly dispersed rather than forming a windrow on the surface.

Two other misconceptions Powell dispelled are that people must use “mulching mowers” if they don’t collect clippings and they must mow and collect or rake clippings if the lawn gets too tall.

“Any rotary, side-discharge mower with a sharp blade will cut clippings into short lengths and do an excellent job of dispersing them,” he said.  “Of course you’ll still need to follow the one-third to one-half grass removal rule, and this might mean mowing more frequently than you have been doing.

“If the grass becomes too tall while you’re on vacation or due to adverse weather, simply raise the mowing height three-plus inches, if the mower will go that high, and mow on about a three-day frequency.  Each time you mow, it will cut and distribute the long clippings and they will disappear after a few mowing times.  You can gradually lower the mower height by one-fourth or one-half inch increments until it reaches the normal mowing height.”

Homeowners who do not remove clippings can still have an attractive lawn by mowing often enough to remove no more than one-third to one-half of the growth at one time and using a sharp blade. A dull blade will not cut grass to the shortest possible length, leaving more clippings on the surface.


Writer: Ellen Brightwell 859-257-4736 ext. 257
Source: A.J. Powell 859-257-5606