When Leaves Drop

FOR IMMEDIATE RELEASE
October 8, 2009

Fall is a beautiful time of year when the colorful displays of nature bring enjoyment to the season. But when the leaves from trees and shrubs start to drop, homeowners are left with decisions on how to effectively manage the load of leaves on their lawns and planted areas.

There are several options for disposal or onsite use, says Tony Bratsch, one of our University of Illinois Extension horticulture educators. Most towns and cities offer curbside leaf pickup. Some require bagging of leaves while others prefer bulk piles that can be vacuumed from the street and loaded loosely onto hauling trucks. Loose leaves are often used for bulk composting at large-scale facilities. Bagged leaves usually end up in landfills and are not recycled into the environment.

Many municipalities allow curbside leaf burning or burning piles in the yard. But, Bratsch says there are environmental and health issues associated with burning. Burning causes localized air pollution and respiratory aggravation, making breathing more difficult for people with allergies and asthma symptoms. Often, specific days are allowed for burning based on fire safety and atmospheric conditions related to smoke dispersal.

"To limit stress on landfills and to avoid burning, you can use the leaves in your landscape," suggests Bratsch. "If you have a light covering of leaves, the first option is to simply mow and shred the leaves, leaving them on the lawn. Mulching mowers are particularly effective in shredding leaves. The shredded leaves will settle through the lawn and provide valuable organic mulch that will help improve turf growth. Just don't smother growing grass with shredded leaves. And for lawns with high levels of thatch, it is better to rake and remove the leaves."

Leaves can also be used as an organic mulch around the base of landscape plants. Mulch helps conserve soil moisture, inhibits weed growth, and recycles nutrients into the soil. Mulch also helps reduce soil compaction and erosion, keeps soil cooler through the hot summer months, and helps moderate soil freezing in the winter.

"Shredded leaves make a better mulch than whole leaves because they decay faster and do not easily blow away," explains Bratsch. "A mower with a bag attachment is handy for leaf collection. Piles of leaves can also be shredded through repeated mowing and then raked by hand. Raking leaves onto a plastic tarp is an ideal way to move large volumes of leaves."

How deep should a leaf mulch be? For trees and shrubs, apply no more than 4 to 6 inches deep. In perennial flower beds, apply 2 to 3 inches.

Leaves can also be used in the vegetable garden for pathways, incorporated into the soil, or left on top of the soil as a "sheet compost" layer. Chopped leaves can be applied as a mulch for perennial crops such as asparagus, rhubarb, and small fruit plantings such as raspberries and gooseberries.

For garden walkways between rows or raised beds, apply a thick layer of leaves to allow easy and clean access to the garden in wet, muddy conditions. Tilled into the soil, leaves are ideal for soil improvement. Apply a 6- to 8-inch layer to vegetable gardens, annual flower beds and newly developed perennial planting beds. The leaves should be incorporated to ensure soil contact and faster breakdown during the winter. To hasten leaf breakdown, apply a small amount of nitrogen fertilizer as the leaves are being tilled into the soil. If your vegetable garden is too wet to till, apply a thin 2- to 3-inch sheet compost layer and then spade or till in the leaves as soon as possible in the spring.

Leaves can also be used in a compost pile. Shredded or whole leaves should be pressed down and layered with small amounts of soil, organic household waste, and fertilizer to stimulate breakdown over the winter. For more information and composting techniques, visit this U of I Extension website: http://web.extension.uiuc.edu/state/hort15.html.

There are many options for managing leaves in the landscape. Most homeowners find that a combination of methods works best to solve their leaf disposal problem.

Source: Anthony Bratsch, Extension Educator, Horticulture, bratsch@illinois.edu