Mulching leaves in lawns has been shown to have no negative effects and is a practice you should consider for your clients because it will improve the soil and eliminate leaves going to landfills. However, this should be done several times during the fall to prevent leaf buildup that damages turfgrass. The following is more information.
Trees will be dropping their leaves soon and it is important to prevent a heavy layer of leaves from building-up on your turf before winter. Heavy layers of tree leaves will shade the grass can smother and kill grass yet this fall. Plus tree leaf cover favors a damaging winter turf disease called snow mold. The easiest way to dispose of leaves is to simply mow them into the turf. Regular mowing during the fall will chop the leaves into small pieces and allow them to filter into the turf. Research at many universities shows that tree leaves can be mulched without any detrimental effects on the soil or turf regardless of turf or tree species. Actually, just the opposite may be true where tree leaf mulching may help improve the soil. Mulching leaves with a mower is much easier than raking, blowing, and/or vacuuming the leaves like we have done in the past. Plus it disposes of the leaves without filling up our landfills and saves our cities thousands of dollars in disposal costs. Regular mowing over dry leaves is most effective for this, but deep layers of leaves or wet leaves may require raking. Heavily wooded lots may also require leaf disposal because of the sheer volume of tree leaves.
Information adapted from the 10/25/2007 edition of the Turf Tips newsletter from Purdue University.