How Can Leaves Be Lunch for the Lawn? Here’s a Primer
Sometimes I need to be reminded I’m too close to a subject. Yesterday, when I posted my “Free Lunches For the Lawn” book excerpt, I received a few private emails from folks who didn’t understand how leaves, grass clippings and other materials could become food for the lawn. It seems evident to me, but that’s only because I’ve been dealing with this subject for years.
To help the lay person understand this, here’s a primer:
1) THE SOIL FOOD WEB — Take a look at the graphic created by Dr. Elaine Ingham. From 30,000 feet, this graphic describes how all living things are interconnected in our ecosystem. In the natural order of things, if left undisturbed by pesticides and chemical fertilizers, everything becomes food for everything else. When something is eaten by another creature, it is digested and excreted and that excretion byproduct becomes fertilizer that plants can then use to grow larger. So, in a nutshell, when leaves are eaten by worms and other soil organisms like bacteria, nematodes, protozoa and fungae, that’s how the leaves eventually wind up as lawn food.
2) THE BACTERIAL FUNGAL SCALE — Dr. Ingham has further explained that all plants have ideal soil profiles within which they are most likely to succeed. Grass plants, for example, like a lot of bacteria in the soil; trees, on the other hand, tend to prefer a bounty of fungal material. Landscape professionals who understand and embrace the Soil Food Web can modify their applications of fertilizers, composts, compost teas and other soil amendments to impact the levels of fungal and bacterial content in the soil. All the lay person needs to remember, though, is to think like a plant. That means that grass clippings make great fertilizer for grass and wood chips and sawdust make great fertilizer for trees and shrubs. That doesn’t mean, though, that you can’t put some sawdust on lawns or some grass clippings around trees. It’s all about finding a common-sense balance.
3) PLANTS SWEAT TOO — Left relatively undisturbed for a period of time, plants will begin to attract what they need from their surroundings. They do this by sweating — or exudating — from the roots. These exudates attract organisms in the natural environment in much the same way humans and other animals attract each other through smell. As gardeners, when we apply composts and a good balance of other natural materials, the plants will naturally select what they need to become healthy.
4) PROVIDE A BUFFET — You don’t need to become a soil scientist to be successful as an organic gardener. They key is to provide a balanced diet. The most balanced, in general, is compost. You wouldn’t, in other words, try to fertilize your lawn with just coffee grounds, or just wood ash, too many leaves, or too much of any one thing — except compost. Compost is really the only thing that cannot really be overapplied. Within reason. Any lawn will need at least 50 percent top soil, too, to provide the physical structure necessary for a weight-bearing lawn.
5) FOR A DEEPER UNDERSTANDING — The best layman’s book on the subject of the Soil Food Web and how raw materials become lawn food comes from Jeff Lowenfels and Wayne Lewis. Teaming with Microbes became a national best-seller — despite its title — because it makes a complex topic so darn easy to read and understand. Jeff, below, is one of the preeminent speakers on the subjects of gardening and soil science on the planet and he’s always open to traveling from his home in Alaska to just about anywhere in the U.S. or Canada.