Fall foliage draws leaf peepers outdoors to glimpse the colors, and enthusiastic yard-tenders to the garden shed reaching for their rakes. Or worse, for their leaf blowers. The gas-powered lawn tools run on rudimentary, inefficient engines; the motors put only about 60% of the fuel you put in to work making wind, while the rest is emitted as aerosols. This medley of carbon monoxide, nitrous oxides, and hydrocarbons is 300 times more potent than what comes out of the tailpipe of a pickup truck.
Even if you are using a rake, you might want to slow your roll. Though many towns and states collect and pool lawn waste to turn into communal compost—the EPA estimates 22.3 million tons of yard trimmings meet this fate—some 10.5 million tons, including leaves, wind up in methane-spurting landfills each year. Yup, you can add obsessive leaf-clearing to the list of sins of the American lawn, right alongside all the water it sucks up and the native species it pushes out.
Everything that lives on your personal patch of turf—from the insects in the soil to the trees themselves—depends on nutrients in those dead leaves and the habitat they can create within the topsoil. Keeping that plant matter in the system is crucial to the nutrient cycle of your lawn’s microecosystem.
“The best practices for leaves are just like the best practices for water,” says Doug Tallamy, an ecologist at the University of Delaware and founder of Homegrown National Park, a group dedicated to restoring our yards’ natural ecosystems. “You want all the water that falls on your property to stay on your property, and you want all the leaves that fall on your property to stay on your property.”
But not everyone can just let tree detritus pile up on their grass. Even responsible people may feel compelled to succumb to pressure from nosy neighbors to rake, or they may be required to do so by an HOA. Even if that’s the case, there are still ways to practice responsible leaf removal, and there are levels to how this can work:
Good: Compost your leaves
If you need to remove the leaves entirely, pile them into a compost heap on your property (although some HOAs get bent out of shape about those, too). You can eventually spread the composted leaf litter, which is naturally rich in nutrients like phosphorus and nitrogen, around the yard as a replacement for mulch or fertilizer.
Better: Pile leaves in tree beds
Rake the leaves under your trees. As an added measure, consider increasing the size of your garden beds, especially those that are directly under those conifers. Why’s that? “If you remove [leaves] from your property, you’re starving all the plants,” Tallamy says, referring to substances like nitrogen, sulfur, and calcium that flora feast on. “We want to close the nutrient cycle. That means keep the leaves on your property, particularly under the trees that made them.”
Best: Leave the leaves
Let the leaves fall where they may. That litter scattered across the ground helps maintain soil moisture, provides winter homes for birds, bats, bees, and bugs, and harbors bacteria and fungi, which together help break leaves down into usable nutrients for trees and plants. “The leaves are creating a blanket over the soil community that maintains the soil humidity, because everything in the soil requires high humidity,” Tallamy says.
Additional reporting by Olivia Gieger.