Why You Shouldn’t Rake Your Leaves This Fall

The weather is getting cooler, the air is feeling crisper, the leaves are turning yellow and red falling from their trees — and this year, leave those leaves be! 

It’s a common misconception that leaves always kill the grass they fall on. Aside from the fact that it’s time to ditch our lawns in the first place, fallen leaves are very beneficial to your soil, trees and plants, and the ecosystem of your backyard. By bagging them up and hauling them away, you are removing a valuable natural resource from your yard.  

If you have a yard or live in a neighborhood with other tree-filled properties, you’re likely familiar with the cycle of filling up large bags of leaves and putting them on the curb to be taken away. A lot of the time, unfortunately, these leaves aren’t being composted, but are taken straight to landfills. In 2018, 10.5 million tons of yard trimmings went to landfills, which was about 7.2% of all municipal solid waste landfilled. Yard debris as a whole account for 13%. When organic matter goes into a sealed landfill, there isn’t enough oxygen for it to properly decompose. As it breaks down, it produces methane: a harmful greenhouse gas even more potent than carbon dioxide. In all, solid-waste landfills are the third-largest source of human-made methane emissions in the U.S.

Here’s why you shouldn’t remove leaves from your yard and garden, and how to handle them instead. 

They Deliver Nutrients Back to the Soil 

Rather than buying fertilizer for the yard or garden, just leave the leaves be! They break down naturally over time, delivering nitrogen, phosphorus and potassium back to the soil as they do — and what gardener doesn’t want free fertilizer? This is, after all, the natural cycle that leaves take. In just one acre of temperate forest, two tons of leaves fall every autumn, which are hosts to beneficial microorganisms that break down these leaves, allowing the nutrients to be taken up by the trees again. These microbes also create a richer, healthier soil for growing your plants. By removing these leaves, we deprive trees and other growth of this important resource to sustain themselves. 

They Sustain Wildlife Populations 

To wildlife, fallen leaves also function as bedding and nesting material. Some animals like frogs, toads, and salamanders — depending on your region — hibernate under leaves in the winter. It also serves as a food source for insects like spiders and slugs, who are beneficial insects for your garden. Having insects means that other larger predators will come to your yard too. Caterpillars, for example, provide food for birds, thus promoting a more robust ecosystem right outside your window. Fostering a biodiverse yard will in turn help the biodiversity of your community, allowing native species to thrive and support one another in maintaining an active, healthy ecosystem: something that’s often lost when humans develop natural areas, displacing wildlife and removing their sources of food.

They Suppress Garden Weeds and Support Soil Structure 

Fallen leaves act like mulch, keeping down competing plants like weeds and shrubs. The leaves will also regulate the temperature of the soil and improve soil structure, making heavy soils more porous and sandier soils more able to retain and conserve moisture. If you experience a lot of compaction or erosion from rainfall in your garden, leaves will help alleviate both. Not to mention, traditional mulch can be quite expensive at garden centers. 

How to Leave Leaves 

Sure, you can just leave them be. But, if you want to make the most out of your leaves, here are a few ways to handle them. 

Mow Over Leaves 

It might seem counterintuitive to run over leaves with the mower, making an even bigger mess — but in many cases, it’s the best first step in letting leaves work their magic.  

If the layer of leaves on your lawn is relatively thin — about an inch or less — there’s no need to move it at all — just leave them on the lawn and mow them over to kickstart decomposition, allowing the nutrients to return to the soil more quickly.  Wait until they are mostly dry before going over them with the lawnmower, a mulching mower, or a mulching attachment on a traditional mower. An extremely thick pile of leaves will trap moisture and keep out sunlight, preventing the grass from photosynthesizing, in which case one of the following methods might be more appropriate. 

Layer the Garden

Using leaves to layer garden beds is a good option if you have an excess amount to deal with, or you prefer not to leave them in your yard. Rake the leaves onto garden and flower beds, or around the base of trees — they’ll suppress weeds and eventually decompose to support soil. If they’re large leaves, shred them in the mower before layering. Generally, between 2-4 inches is ideal (more for trees, less for perennial plants).

Reclaim Spent Soil 

Growing healthy, robust plants requires healthy, robust soil — and leaf mold might be just the soil amendment you need. Just let them decompose atop a section of the yard with poor soil. The lower part of the pile will decompose well, and the top layer can be turned under the soil in the spring.

Build a Wildlife Shelter

Create a brush shelter in the corner of your yard, if you have space. A simple pile of branches, leaves, sticks, and other yard waste that will be helpful for overwintering insects and nesting animals in the cold winter weather.

Other Ways to Handle Leaves 

It isn’t always possible to let leaves decompose on your property. Maybe you don’t have room for the piles, or don’t have a large enough yard to spread them out, or rent a place that requires you to remove leaves. It is true for city-dwellers that leaves left on yards can wash into streets and clog storm drains. In that case, composting can offer a great solution. 

Compost

If you maintain your own at-home compost bin, you know the importance of adding brown matter to the pile. Keep a pile (or box, or bag) of leaves next to the compost or in the garage, and add it slowly to your food scraps throughout the winter. They’ll decompose even better if you shred them with the mower beforehand. 

Compost Drop-Offs and Pick-Ups

Sometimes, leaf pick-up services do actually take the leaves to be composted. Look into your city or municipality’s processes for handling leaves, and confirm that they will indeed be recycled. Some cities will have programs that either compost the leaves or turn them into mulch, and then offer those products back to gardeners to use. Otherwise, companies will even come and collect all of the leaves for you to be composted.