Considered as one of the most strenuous annual chores when owning a home, dead leaves blowing in from a neighbors yard or just simply blowing makes one understand the invention of the chain saw. They provide shade in the heat of summer and spectacular color in autumn but the most important function of leaves on deciduous trees is to die and fall to the ground.
Healthy soil consists of many organisms including bacteria and fungi. Both microbes are major contributors to the soil food web. Bacteria thrive on green food. A perfect example would be grass clippings dispersed on the freshly cut lawn. Fungi love brown food. That resource is readily available as dead leaves. Grass clippings and chopped leaves are an invaluable supply of organic matter that feed the bacteria and fungi.
Feeding the microbes is how we fertilize the lawn in the organic world. Through photosynthesis, carbohydrates and proteins are carried throughout the plant and then get secreted out through the roots as exudates. Those exudates attract bacteria and fungi, which live in healthy soil. As the plant roots grow the excess root tissue along with organic matter feed the bacteria and fungi. All of this fun stuff happens in about a 1/10 of an inch surrounding the roots called the rhizosphere.
What happy days these must be for the bacteria and fungi with all that free food. If only life was that simple.
Unfortunately for them, everything in nature has a predator.
Theirs in this case would be bigger microbes called protozoa and nematodes. They eat the bacteria along with the fungi. What they excrete is taken up by the plant and used as nutrients.
Pretty simple way to feed a lawn isn’t it? It gets nutrients without any help from you or I. It’s even more amazing when you realize there are billions of microbes in just a tiny amount of healthy soil. It’s a pretty busy place.
So the kill or be killed saga continues in the soil. Protozoa and nematodes are then eaten by arthropods, which are insects and spiders and they in turn are eaten by either each other or larger arthropods along with birds, snakes or other animals. All this decaying and excretion feeds the plant. This whole process we’ve been talking about is called the soil food web. All the members of this web are continuously looking for carbon to consume which is what they and organic matter are all made up of.
Suggesting chopping the leaves on ones plot instead of raking them, generally receives a reaction of bewilderment. Mowing the leaves onto the lawn is simply one of the most beneficial practices you can do for beautiful grass. Obviously, mowing fallen leaves that are several inches thick is not practical or even possible with home owners lawn equipment but when mowed as the gradual leaf drop begins it saves lots of labor come the final clean-up.
Chopped leaves dissipate much quicker than one would think. Even as the heavier drop occurs, one can start mowing in the middle of the lawn area and continuously push the leaves to the perimeter, leaving a light coat of mulch behind available to wanting fungi. Concerned the layer is too thick? Just mow again until the leaves are finer and decompose faster.
If you’re lucky enough to have deciduous trees, use them.
Increasing organic matter in soil to a level of at least 5% is the most important thing one can do to improve the health of a lawn or any plant. Organic matter retains moisture while improving drainage, it alleviates compact soil, holds on to moisture while providing nutrients slowly to plants, buffers pH and most of all it contributes biology and their food. Certainly nothing a bag of chemical fertilizer can give you.
And it’s all free.