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How Does a Grass Catcher Work?

By James Young ; Updated September 21, 2017

Grass Catchers

Without grass catching systems, mowers discharge large amounts of cut grass onto lawns. When deep clippings block light, grass dies unless homeowners collect the waste and carry it away. Grass catchers mounted on the exhaust ports of cutting decks eliminate the need for raking the lawn. Simply empty the bag or bin in a compost heap or other disposal area and continue mowing.


Rotary mowers cut with spinning blades which act much like high speed fans, lifting and throwing grass clippings as the mower moves across the yard. Heavy steel decks surround the blade to protect operators from accidental injury. These decks contain a side port through which clippings are expelled, along with an occasional stick or stone struck by the blade. Normally a deflector shields the outlet, forcing dangerous debris downward.

Grass catchers may be attached directly to the debris port, or be installed on a second port to the rear of the deck. With a grass catcher in use, the remaining deck port is plugged with a plastic block. Without the catcher, either a plug or metal hatch secures the catcher port. Only one port should be open at any one time.


Grass catchers of many types use similar methods for collecting waste clippings. Most combine the collection chamber with a filter which separates clippings from the airflow. Walk-behind mowers use a mesh bag in a rectangular frame which covers the port and hangs from the mower handle. When the bag fills, the operator lifts it from the mower and discharges the grass away from the lawn.

Riding mowers often use bins rather than mesh catchers. Plastic trash bags fit receptacles in the catcher. Grass clippings travel through a large tube from the debris port to the catcher and the heavy clippings drop into the bags. To empty the catcher, seal the filled bags and set them aside, then place new bags in the bins and continue mowing.


Grass catchers frequently clog. Damp clippings seal off the walls of mesh catchers and clippings stop flowing into the bag. Wet grass often builds up on the walls of exhaust ports and tubes, blocking the flow of the waste grass. Catchers work best in dry conditions. When working in tall grass, set the mower to cut only two or three inches of the stand in one pass.


About the Author


James Young began writing in 1969 as a military journalist combat correspondent in Vietnam. Young's articles have been published in "Tai Chi Magazine," "Seattle Post-Intelligencer," Sonar 4 ezine, "Stars & Stripes" and "Fine Woodworking." He has worked as a foundryman, woodturner, electronics technician, herb farmer and woodcarver. Young graduated from North Seattle Community College with an associate degree in applied science and electronic technology.