Do Unraked Leaves Kill Grass?

Unless you have a very heavy layer of leaves, they won't smother your lawn. Most lawns are going dormant by the time leaves start to fall, so the myth that leaves will kill grass is false. Leaves biodegrade, of course, and they'll decompose by the spring.

Should leaves be left on lawn over winter?

Excessive leaf matter on your lawn going into winter is bad for several reasons. First, it will smother the grass and if not removed very soon in the spring it will inhibit growth. Second, it can promote the snow mold diseases. And finally, turf damage from critters (voles, mice) can be more extensive in the spring.

Is mulching leaves bad for your lawn?

A study by Michigan State University indicates that mulching is 100 percent beneficial for the lawn. Mulched leaves are decomposed by earthworms and microorganisms and turned into plant-usable organic matter. Mulched leaves are better for the greater community, too, because they stay on-site and out of landfills.