Benefits of Fallen Leaves

Fallen leaves, as an additional physical layer of organic materials above ground, provide food, shelter, and nesting or bedding materials to a variety of wildlife, as well as overwintering protection for a number of insects, all of which work together to contribute to a healthy yard.1 The soil itself is also a beneficiary of this autumnal gift of fallen leaves, as the leaves are essentially composted over time into nutrients that feed both the next year’s ‘crop’ of grass, but which also feed a vast number of microbes in the soil, which are actually the most important ‘crop’ you can grow, considering that all plant life in your yard depends on a healthy soil biology.

According to National Wildlife Federation Naturalist David Mizejewski, “Fallen leaves offer a double benefit. Leaves form a natural mulch that helps suppress weeds and at the same time fertilizes the soil as it breaks down. Why spend money on mulch and fertilizer when you can make your own?”

Maximizing the Benefits

However, just leaving the leaves to lay where they fall in the autumn (see what I did there?) isn’t the most effective way of getting the most benefits out of them, as sometimes they can really pile up in areas where they may effectively smother a section of the yard, but there are a number of different ways to approach your leaf harvest, depending on your particular situation.

As one plant and soil specialist, Dr. Thomas Nikoai of Michigan State University, put it, leaving the leaves on the lawn is ” … not only not a problem, it’s awesome.” According to an interview at Christian Science Monitor, Dr. Nikolai says that by mowing over the fallen leaves to turn them into smaller pieces, the leaves will actually enhance the lawn’s fertility, not kill it off. And while it’s usually recommended to use a mulching mower, or a mulching attachment, to convert the larger leaves into smaller-sized particles, virtually any mower can do the job, and it’s merely a matter of mowing over the leaf-filled yard a few times during the season.2

However, if you’re cultivating a ‘tidier’ look to your lawn, and don’t want those pesky dried leaves getting in the way, they can be raked into garden beds, flower beds, or as a mulch around trees, either as-is or by using a bagger on your mower to collect them. Covering garden beds with a thick mulch in the fall can be an effective and simple way to build soil fertility, as well as helping to keep the yard look tidier.

And far be it from me to encourage you to use lawn equipment in a way that it’s not intended, but I’ve heard that you can put leaves into a large trash can and then use your weed-eater in the can to slash the leaves into tiny bits for use as mulch.

Leaves can be a great additive to a home compost pile, and by keeping a pile of it next to the compost, leaves can be used to cover layers of kitchen food waste throughout the winter.3 Fallen leaves can also be used to reclaim sections of the yard that are marginal, just by building a huge leaf pile there and letting it sit all winter. By the spring, the lower part of the leaf pile will be converted into rich soil, while the middle and top layers can be used as mulch or dug into spring garden beds as a soil amendment.