If you hate raking leaves, get ready to rejoice! As the Northern Hemisphere enters late-autumn, fallen leaves weave a warm tapestry that blankets the earth. Not only are these leaves beautiful, they serve an important ecological purpose, which is inhibited when the leaves are raked up into yard waste bags and shipped off-site. Leaves create a natural mulch that recycles nutrients back into the soil for plants to use the following spring, and even grass can benefit from allowing the leaves to perform their soil-building duties.
To get the most benefit out of fallen leaves in your own yard, some human tinkering may be necessary. Mow leaves using your lawnmowers mulching fuction to encourage decomposition and allow shredded leaves to be quickly broken down into soil. For those who prefer a leaf-free lawn but still want to build soil, the leaves can be placed in garden or flower beds, concentrated near trees, or simply mixed into a compost pile with kitchen scraps. Ideal compost contains two parts carbon rich matter, like dead leaves, wood chips, or straw, to every one part nitrogen rich matter, like food waste and green plants. Fallen leaves add incredible value to a healthy compost pile.
Every autumn, deciduous trees lose their leaves as a natural mechanism to conserve water during the cold winter. Leaves are often porous to allow greater absorption of water during the growing season. As the summer ends, green chlorophyll cells break down and the leaf’s yellow and orange leaf pigments become visible, while other seasonal chemical changes create red pigments. As humans prepare for frigid temperatures by sealing drafty windows, trees drop their leaves to seal up their living tissue and water supply.
Fallen leaves then form a layer of mulch, which protects the roots and soil from harsh winter weather and provides habitat and nourishment to invertebrates and microorganisms. The temperate forests are self-mulching, self-composting ecological systems, thanks to seasonal changes. The leaf mulch facilitates the building of a robust soil ecology, which in turn benefits plant health. “Fallen leaves offer a double benefit, says National Wildlife Federation Naturalist David Mizejewski. “Leaves form a natural mulch that helps suppress weeds and fertilizes the soil as it breaks down. Why spend money on mulch and fertilizer when you can make your own?”