Let’s Talk About: Leaving the Leaves
What’s all the fuss about?
A beautiful yard full of luscious green grass with a white picket fence is often included in the description of the American Dream, a little piece of land to call your own. And to many, having a meticulously manicured lawn is still important to them.
Personally, I can never figure out how to mow in a way that creates the baseball field patterns, and our grass grows so fast that at peak times, mowing it twice a week is a challenge enough. It boggles my grandmother’s mind that I don’t bag my grass clippings. And how many times have I heard other’s lament on a stranger’s “messy lawn” because it hasn’t been mowed all season. As it turns out, lawns can be rather contentious.
In the summer, if you mow your lawn frequently enough, the clippings are so short they blend right into the grass. What’s even more confusing is the autumnal ritual of bagging leaves. I’ve never understood why people bag biodegradable material into plastic bags to be thrown away and now take centuries to decompose instead of decades.
I can remember it as a kid, hopping in the bin to stomp the leaves down so we could pile more into the bag, then leaving them out for the town to collect in their annual brush clean up. But when I finally became a homeowner, at the discontentment of my husband, I was adamant about leaving our leaves. Before I explain why, let’s looks at some introductory plant biology.
Roots and Shoots
No it’s not a board game, I’m talking about the two most basic components of a plant; the roots and shoots, or more technically put, belowground biomass and aboveground biomass. These two systems serve different functions for the plant.
The belowground biomass consists of living roots, root hairs, and any energy storage such as tubers, bulbs, or rhizomes. The purpose of the root system is to extract nutrients and water from the soil to provide to the plant.
The aboveground biomass consists of the stems, leaves, flowers, and seeds. Aboveground biomass growth is driven by the sun, harvesting energy for the plant by converting sunlight to sugar in a process called photosynthesis.
For many species, primarily deciduous ones, the greatest period of root growth occurs in the fall and winter, when the aboveground biomass is dormant1.
The Chemistry of Leaf Litter
Leaf litter is an essential nutrient source for soil and the plants that grow in those soils. Dead leaves are comprised of the very nutrients that plants extract from the soil, such as carbon, nitrogen, and phosphorus2. As the leaf litter decomposes, these nutrients are released to the soil at different rates. This annual pattern of dropping leaves essentially fuels nutrient recycling within a forested system3.
And while this process does take years, because it is ongoing, the ever refreshing and decomposing leaf litter delivers a steady source of nutrients, essentially, leaf litter is fertilizer.
This type of self reinforcing habitat is showcased in other environments as well, like the acidification of soils by sphagnum moss which needs acidic soils to grow4. This is likely a product of coevolution but let’s not dive into that rabbit hole just yet.
What To Do With All Those Leaves
So we’ve established that bagging leaves isn’t the best option, for your lawn or for the environment. Some advocacy groups suggest leaving the leaves in place, as this provides habitat and resources for wildlife from amphibians to birds and small mammals. However, I don’t really want my lawn to mimic the forest floor, and I don’t want it to serve as wildlife habitat. I have set aside other pieces of my property to function for those things and value having a yard.
As I mentioned at the beginning of this post, lawns are contentious. Not just receiving criticism from those that prefer spotless grass, but from the other extreme that suggest there shouldn’t be any lawns, all space should be used to grow food and provide habitat. But that’s another post for another time.
Here’s what I do
My husband and I spend a sunny fall day mowing our leaves into a circle, raking the areas along the edge of the yard and tough to reach spots into the middle (which also gave small critters a chance to get away safely).
Once we mow the leaves into a pile in the middle of the yard, my husband mows outward in a concentric circle pattern to distribute the mulched leaves evenly. Watch the video below to see us putting this plan in action this past October! These partially broken down leaves will continue to decompose through the fall, and in the spring with the snowmelt and rain.
Once the grass begins to grow in late spring, it will push through any remaining leaf mulch and after the first mow of the season, the leaves have been completely incorporated into the lawn.
Okay, so now that I’ve detailed how we go about our leaf maintenance, it’s time to address if this will work for you. Below I’ve outlined the benefits of this method, but also some challenges depending on different scenarios.
| Benefits | Challenges |
| This is a relatively quick fall chore. Two hours took care of our entire property (0.6 acres but all lawn space). Compared to raking and bagging leaves, this took a fraction of the time. | It’s difficult for those using non-motorized mowers as sticks, acorns, etc may get caught in the blades. This method is more easily accomplished with motorized push mowers or riding lawn mowers. We purchased our riding lawn mower used and refurbished four years ago for $1,000. |
| Free fertilizer. As outlined above, leaf litter provides essential nutrients that plants of all kinds need to grow, including your grass, at a time when they need it most. This saves money and resources by skipping the home improvement store bagged fertilizer. Additionally, fall is a better time to fertilize lawns because there is less precipitation than in spring, meaning less run off. You keep the nutrients in your yard and they don’t run into our waterways. | This method may be less suitable for someone with a significantly sloped yard or a yard with more trees. All of the trees in our yard are on the perimeter, which better facilitates the concentric circle mowing pattern. Perhaps a randomized pattern for a more difficult lawn would suffice. |
| Environmentally friendly choice. Bagging leaves and bringing them to the municipal dump prolongs the otherwise quick decomposition process into a centuries long affair. At best, your municipality runs a waste to energy facility, like my town, where the leaves will be burned and the ash buried which provides electricity from the combustion process and reduces volume of the waste. But this is still a less desirable option than mulching your leaves into the soil. | If lawn maintenance isn’t within your control. For individuals who live in condos or similar type housing where lawn maintenance is provided for you, you might not have a say in how it’s performed. Educating the entity responsible for lawn maintenance (e.g. HOA) on other alternatives may be effective. |
Ultimately, there is no one size fits all when it comes to yard or property maintenance, especially when accounting for regional differences. However, if you’re looking for an alternative to stuffing leaves into dozens of bags to leave by the road side to be collected, I highly encourage you to try out this method to see if it works for you!
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