The answer to this question isn’t super simple, but it’s not overly complex. I’m going to offer some insight and by the end of this post you’ll be able to make a well informed decision on whether or not you should rake your leaves every fall or let them stay put.
There are a few angles to consider. Let’s start with soil health.
The foundation of the landscape is the soil. To develop healthy mature plants, healthy soil is required. A healthy ecosystem is excellent at building soil with no human effort required. We don’t need fertilizers, “mulch”, chemicals, etc. when we put the right plants in the right place. It gets a little tricky though…
Through neighborhood development and home construction, we destroy a lot of natural space and we create impermeable surfaces like driveways, sidewalks, and roofs, we install lawns and plants that don’t agree with our natural environment and require a lot of human input to maintain. Somehow this has become the norm. However, we don’t have to choose the “normal” way of doing things, and we can choose a fair compromise between what makes sense and what everyone else is doing.
Let’s dive into the qualities of a natural ecosystem, i.e. the landscape that existed before our homes arrived.
Natural and Unnatural Ecosystems
A natural ecosystem is a community of living and nonliving organisms that interact together through biological, physical, and chemical processes. Things like soil, plants, water, air, sunlight, micro organisms, animals, etc. These are self sufficient, balanced ecosystems, with a high amount of native biodiversity and minimal human disruption.
Humans in developed areas are excellent at creating the opposite of this – unnatural ecosystems. These unnatural ecosystems typically occur in agricultural or urban areas that are greatly modified and require high levels of human maintenance. So where do we find the balance?
Finding the Balance with Nature
In natural ecosystems, no human maintenance is needed and therefore no leaf raking required. Unnatural ecosystems typically require a lot of leaf raking (and other maintenance tasks).
If we can begin to designate small parts of our yards and gardens as natural areas, and we start choosing location appropriate plant species, we can start reducing the amount of human impact (i.e. leaf raking) required to maintain the space.
Many trees and shrubs naturally drop their leaves in the fall, and they distribute them evenly across the ground. They don’t do this for fun, or because they’re lazy and don’t want to hold their leaves any more. They drop their leaves in the fall to conserve water, energy, and help them survive harsh winter conditions. There’s more… These leaves contain valuable nutrients, which are reabsorbed into the roots of the trees and shrubs and stored for later use. The fallen leaves build up a layer of protection for the soil and plant roots and help protect from harsh winter winds and maintain soil moisture to prevent drying out.
Still more… Dead plant (leaves, twigs, flowers) and other organic material (insects, worms, etc.) start to decompose and are broken down by microorganisms in the soil (fungi and bacteria), which extract most of the usable chemical and organic matter and make it available to the plants. Once all the usable nutrient rich material is converted by the microorganisms, you’re left with something called humus.
The Humus Miracle
Humus is made of mostly carbon, it’s organic, but microorganisms just can’t decompose it any further. Humus is incredibly stable and can remain in soil for hundreds of years.
So what’s the point of humus?
Humus acts like a giant sponge that can hold an incredible amount of water. Humus rich soil will remain moist for weeks longer than soil lacking humus. Many of these amazing plant nutrients unlocked by the microorganisms can essentially stick to this humus sponge and not get washed away by rain. When the plant roots come into contact with the humus, they can take in the nutrients they need to develop into healthy mature plants.
The more humus available, the healthier the plants. It takes many years to develop healthy humus rich soil, so it’s time to start thinking about it if you want to enjoy the benefits in your yard or garden. You can build humus faster by adding more organic matter to your soil throughout the year. Real humus can’t be bought and there is no secret shortcut. In this case, you must let nature do it’s thing.
Natural and Unnatural Ecosystems Working Together
By developing natural areas on your property, you can begin to let nature take its course, let leaves fall into place and become part of a balanced system. On the unnatural areas or developed areas on your property, it typically makes sense to rake the leaves, especially off of impermeable surfaces like sidewalks and driveways.
And be mindful of the fact that where your house and impermeable surfaces exist, leaves would usually fall into place. Now leaves get displaced into other areas of your property, or you can get rid of them through city composting programs.
It’s not ideal to take all of the displaced leaves and debris and put them into the smaller natural areas on your property. This wouldn’t usually happen in a natural system. The intended leaf coverage may be a couple inches, not something that looks like a pile of leaves. Good soil can’t be built faster by piling an excess of organic materials and cutting off access to air and water. It needs to happen slowly over time.
A balanced solution might involve raking leaves off hard surfaces, like roofs, driveways, patios, etc. and bagging them in refuse bags. These leaves can be picked up and composted by the city or you can create a dedicated compost pile in your own yard (to be discussed in another post). For the natural areas, you can decide whether or not you want to leave your leaves where they fall and start building nutrient rich soil and using them as natural mulch.
Any time humans intervene or disrupt a natural system, especially on a large scale, it’s important to allow natural processes to continue, for the wellbeing of the natural communities as well as ours. We need each other and we can absolutely build a mutually beneficial relationship with our natural communities. The more we start thinking and talking about this relationship, the better it will become for all of us.
* Further reading: Help Garden Bugs Survive Winter Using Fallen Leaves