Will Dead Leaves Kill Grass?

In nature, fallen leaves decompose and eventually become part of the forest floor.

When trees shed their leaves in the fall, the grass growing beneath them has entered the dormant stage that will continue through the winter. A light covering of fallen leaves won't hurt the lawn and will actually feed the grass as they decompose.

Significance

If dried leaves are useful as a mulch to discourage the growth of weeds around plants, it stands to reason that a thick mat of leaves will have the same effect on grass by matting it down and depriving it of sunlight. Excessive amounts of leaves are best added to the compost pile or used as a mulch around perennial plants and shrubs.

Benefits

Leaves provide a gold mine of nutrients that all plants use. According to the Texas Agri-Life Extension, leaves contain 50 to 80 percent of the nutrients that a plant takes from the air and soil during the growing season. Leaves decompose gradually, providing new growth with a natural slow-release fertilizer.

Solution

A good approach to managing dried leaves that have fallen on grass is to run a lawnmower over them. This breaks the leaves down into smaller pieces that will decompose more quickly without smothering the grass, states the Indiana Department of Environmental Management.

References

• Boston Globe; Leaves on Grass: What's at Stake if You Don't Rake?; Beth Daley, Nov. 12, 2008
• Indiana Department of Environmental Management: Yard Waste and Lawn Care
• Texas Agri-Life Extension; Don't Bag It-Leaf Management; Vince Mannino, Robert Richter, Doug Welsh and Sam Cotner