Fall is a season for slowing down, gathering your bearings, and saving your energy for the upcoming winter. All around us, nature is doing just that. The squirrels are stashing away their acorns, perennials are dying back to their crowns to store energy in their roots, the birds are migrating South to warmer climates. The trees have their own way of shutting down, and it comes from their leaves. Those leaves are part of the ecosystem's natural cycle, and they aren't just falling for no reason; they serve a multitude of hidden purposes that benefit the surrounding environment.
1. Insulation
When leaves fall and cover an area, particularly around their own roots, they are providing a sort of blanket effect. They are insulating warmth and moisture into the soil underneath them. By doing this, the soil stays warm and moist over the winter months. This is significant because harsh temperatures and drought are detrimental not only to the tree roots but to any plants that may be growing around them. Additionally, the microbes living in the soil need warmth to survive. These microbes are important for soil health, and without them, the garden would face fertility issues. By leaving the leaves, you are helping your own garden by protecting your plants' roots and soil's beneficial microbes from freezing, allowing your garden to thrive come spring!
2. Overwintering beneficial wildlife
To survive through winter, many beneficial wildlife, such as insects and small mammals, choose to overwinter within plant debris, such as fallen leaves. Insects especially are keen on laying their eggs within the shelter of the leaves. When those leaves are raked up or leaf-blown, the eggs and animals that are hiding within them get hurt and are unable to survive until spring. Many of these creatures serve beneficial purposes to your garden, such as deterring pests and pollinating your flowers; keeping the leaves on the ground allows those creatures to serve your garden in the springtime.
3. Natural fertilizer
Everything in nature is a cycle: as the fallen leaves decompose, they return their stored nutrients to the soil, increasing its fertility. Nutrients such as carbon and nitrogen are stored within leaves during the growing season, and as they decompose, they give these important nutrients to the soil. These are nutrients that plants need in order to survive, and by allowing nature to run the natural process of delivering them to the ground, you are saving a lot of money and labour on fertilizers and other soil supplements, some of which can be harsh and run off into the surrounding environment, causing harm to other ecosystems.
4. Soil erosion barrier
Similarly to keeping warmth and moisture locked into the soil over winter, leaves provide a barrier against harsh winter precipitation that causes soil erosion. When rain hits the ground, it strikes with a force that can displace soil aggregates, instead of dampening the soil. However, when rain strikes leaves sitting on top of the soil, the water is allowed to percolate at a slower rate, which doesn't damage or displace the soil, and saturates it slowly, allowing the ground to be watered deeper.
5. Increases organic matter content
Organic matter, such as compost, plant debris, and mulch, is vital for the health of your garden. Your soil's Cation Exchange Capacity (CEC), a fancy way of saying the ability of your soil to hold onto nutrients, is greatly improved through the addition of organic matter. It allows nutrients to better hold onto the soil, rather than running off. Additionally, organic matter does a similar good in regard to allowing your soil to hold onto moisture in the soil better. Fallen leaves are a great source of organic matter to add to your soil, and the best part about them is that they're completely free!
What if I understand these benefits, but can't get over how messy my garden looks due to these fallen leaves?
Don't worry! If the unsightliness of the leaves is a bother, there are ways to harness their benefits while still doing minimal harm to the surrounding ecosystem. Here are some ideas for alternative things to do with those fallen leaves!
Mulch with them
Rake or blow your fallen leaves onto existing garden bed spaces, insulating tender plants and preparing your garden for winter. It also saves you from having to go out of your way to a garden supply store to buy mulch!
Create a wildlife brush pile
Rake your leaves into a pile in a quiet, low-traffic area of your yard, or under a tree. You can start with a simple base of small branches and twigs to create some air pockets, and cover them in leaves. If you have them, you can also add logs and pine needles to create a habitat suited to the needs of a greater diversity of wildlife.
Compost the leaves
If you have an existing compost bin in your yard, the leaves are an excellent addition to it; they provide good insulation for the microbes that are working to break down the pile. Remember to turn the pile regularly to encourage air flow and make sure the temperature is evenly spread out!
Make leaf mold
Leaf mold is a great resource for your garden. It provides several benefits, such as nutrients and moisture retention, encourages the growth of beneficial organisms, and improves soil structure. Make it by raking the leaves into an out-of-the-way corner of your yard. Water the pile occasionally during periods of low rainfall and turn it every few weeks. The pile can take up to 3 years to fully turn into leaf-mold, but partially-decomposed leaf mold is an excellent mulch for your garden.
When should you not use fallen leaves in your garden?
1. Diseased leaves
If your leaves show any signs of unnatural spotting, mildew, or fungal growth, it is best not to use them in your garden. These leaves can spread unwanted pathogens throughout your garden that are hard to get rid of.
2. Leaves from toxic trees
Some tree species, such as eucalyptus, have leaves that contain chemicals that can harm other plants. It's best to do your research on what kind of trees you have in your yard and gather an understanding of what kind of benefits or detriments they provide to your garden space.