Green Guru: What to Do with Fallen Foliage
When the fiery red, orange, and yellow leaves fall from the trees and land on your lawn, pilling them high for jumping can be a family affair. And when you’re sufficiently exhausted from diving in the heaps of foliage, you can use the leaves to nourish your garden, shrubs, and trees. Instead of putting them in a bag, mow, mulch, mix, or compost them.
Leaves hold 50 to 80 percent of the nutrients that a plant extracts from the soil and the air during the growing season, according to the Texas Agricultural Extension Service, part of the Texas A&M University System. These nutrients can be reincorporated into your lawn and soils, improving soil structure while the decomposing leaves slow the growth of weeds and keep moisture in the ground.
If you decide to keep leaves on your lawn, mow over them so that they’re shredded, leaving a thin layer on the grass. (You want to be able to see the blades through the pieces.)
Mulching, another alternative, already occurs in the outdoors. “Large trees growing in the forest naturally have a layer of decayed leaves and leaf mold beneath them. This organic layer is the home of many beneficial organisms such as earthworms and mycorrhizae,” reports the Cooperative Extension Service at the University of Illinois at Urbana-Champaign College of Agricultural, Consumer and Environmental Sciences (PDF).
A few extension offices suggest that course of action for homeowners, especially if you have oak trees on your property (the leaves decompose slowly). Shredded leaves break down faster. Putting a three- to six-inch layer at the base of trees and shrubs, and a two- to three-inch mulch on annual and perennial flowerbeds is best. In vegetable gardens, put the mulch between rows, advises the Texas Agricultural Extension Service.
Working leaves into the soil is another possibility. Till a six- to eight-inch layer into clay soil will help aeration and drainage. In sandy soils, the leaves will help retain water and nutrients.
Finally, composting is another option for your fallen foliage. “Knowledge of composting dates back to the early Greeks and Romans. The Arabs kept the science of composting alive during the Dark Ages, and it continued throughout the Renaissance. From Shakespeare's Hamlet comes the line ‘spread the compost on the weeds, to make them ranker!’ In America, the value of composting was recognized by George Washington, Thomas Jefferson and George Washington Carver,” the Texas website explains.
This autumn, once you’ve brushed the leafy remains from your clothes, keep the leaves around and improve your own environment.