Yard Trash: An Inexpensive Source Of Mulch
by Dr. Robert Black, Consumer Horticultural Specialist
 
Pine needles, leaves, grass clippings and plant trimmings have been collected, stuffed in plastic bags and placed on the curbside where they were collected and transported to landfills. These materials accounted for 20 percent of the waste dumped in landfills. Florida has passed legislation that prohibits lined landfills from receiving this so called yard trash as of January, 1992. Much of this yard trash can be recycled on site as mulch.
 
Pine needles, leaves and grass clippings can each be used alone as a mulch or in combination. Of the three, pine needles are the best mulching material. They are attractive, not easily removed from beds by wind or rain, and don't "mat down" excessively. However, they don't last more than 6 months due to rapid decomposition. Leaves can be used alone as a mulch, however, they are difficult to keep in place in windy locations and are easily washed from beds during heavy rain showers. Leaves perform best as a mulching material when they are shredded and\or composted. Grass clippings are the least desirable mulching material. They are easily transported by the wind, decompose very rapidly, and pack down to form a mat which can exclude air and water from the root zone. They should be spread thinly over the ground, mixed with other mulching materials or better yet, composted with other yard waste. Plant trimmings such as twigs and small branches should be shredded before they are used as a mulch. A mechanical chipper/shredder is needed for this process.

Yard trash is readily available in many yards and so it is a very inexpensive source of mulch. However, there is some reluctance to use it as a mulch because it is not as attractive as some of the more expensive mulch materials. This problem can be overcome by adding a thin layer of a more uniform mulch over the yard trash.

Mulch can be used around plants in beds or around individual trees and shrubs in a lawn. Eliminating grass from around plants greatly reduces the competition for water and nutrients from the turf and increases the growth rate and health of trees and shrubs. When mulching individual trees in lawns, create a circle of mulch about 2 feet in diameter for each inch of trunk diameter. Increase the size of the mulched area as the tree grows.

Pull mulch 1 to 2 inches away from the stems and trunks of plants. The high moisture environment created by mulch increases the chances of stem and trunk rot which can result in plant death.

In addition to being useful around plants, mulch can be used as a ground cover for walks, trails, driveways and play and natural areas. It can be used to cover low-growing, tender plants to protect them from frost injury. Mulch can also be composed and used as a soil amendment for flower and vegetable gardens.
 
The amount of mulch to apply will depend on the texture and density of the mulch. Compost and many wood and bark mulches are composed of fine particles and should not be applied any deeper than 2-3 inches (after settling). Excessive amounts of these fine textured mulches around shallow-rooted plants can suffocate their roots causing chlorosis and poor growth. Course textured mulches such as pine needles and pine bark nuggets, which allow good air movement through them, can be maintained at a depth of 4 inches.

Mulches composed solely of leaves or grass clippings should never exceed a 2-inch depth. These materials have flat surfaces and tend to mat together restricting water and air to plant roots.