BM21890: Grass Mulching AttachmentJohn Deere mulching systems use durable blades designed to chop grass into very small particles. The mulch that is distributed across the lawn will turn to feed, eliminating the need for bagging. This improves efficiency by reducing cleanup time. It installs internal baffles and a two? piece plug to keep clippings inside the deck so the blades can chop them into fine mulch.