Don't Throw Leaves And Plants Away -- Compost Them!

Wondering what to do with all the autumn leaves you've raked up from the yard? Try composting them. And while you're at it, toss in those old tomato vines.

"Leaves, plants killed by frost, vegetable scraps and grass clippings--all these materials can be composted," says Dr. J. Robert Nuss, professor of ornamental horticulture in Penn State's College of Agricultural Sciences. "You can start a compost pile now, and the composting process will continue through the coldest days of winter."

Nearly 30 percent of the wastes homeowners throw away each year can be composted. This keeps these wastes out of landfills and creates a product that adds valuable organic matter to the lawn and garden. "Many landfills no longer even accept leaves or garden wastes," says Nuss. "Composting may be the easiest way for homeowners to dispose of them."

Composting decomposes organic matter into a dark, crumbly material similar to humus. Along with providing nutrients, finished compost helps soil retain water by increasing its organic content. "Compost is a valuable soil conditioner that can be used in gardens, around trees and on lawns," says Nuss.

"You don't need a special compost bin, but unconfined heaps can be visually offensive to neighbors," Nuss adds. "If you have neighbors living close by, you may want to consider using a compost bin. Other than that, you need few tools except for a manure or garden spading fork for turning the material, and a soil thermometer."

Composting tools and bins are available at hardware stores and garden centers, or you can order them from gardening catalogs. An inexpensive bin can be made from masonry blocks, boards, wire or snow fencing. "Make sure your bin is at least 3 feet high and 3 feet wide, so that it can hold enough material to function properly," says Nuss.

Once you have your bin situated on level ground, you can fill it with plant and vegetable scraps, egg shells, coffee grounds, sawdust -- even small bits of paper.

The pile should contain a mix of carbon- and nitrogen-rich materials because both are essential for the microorganisms that do the decomposing. "Green, leafy wastes usually are high in nitrogen, while woody materials tend to be high in carbon," Nuss says. "Fertilizer and manure also are good nitrogen sources."

The microorganisms that aid in composting need some moisture, so you may need to water the pile from time to time. One way to gauge moisture is the squeeze test. "Tightly squeeze a handful of the material," Nuss says. "If a few droplets of water come out, it's just about right. If it looks and feels dry as a bone, hose down the compost pile."

Decomposition without oxygen can cause bad odors, so turn the pile every few weeks with a fork to aerate it. Using a fair amount of coarse material--dry leaves or bulky plants, for instance -- also helps ensure that the pile gets proper aeration. If you detect any odor, turn the pile.

With proper aeration and ample amounts of carbon, nitrogen and moisture, the pile should reach at least 90 degrees F in the middle, which indicates that the process is working. Temperatures up to 140 F will kill weed seeds, but higher temperatures can kill the composting microbes. Check the temperature once a week with a soil thermometer, and if it gets too high, turn the compost pile.

"As long as the pile is large enough to insulate itself, it will continue to decompose at a slower rate throughout the winter without being turned," Nuss says. "When warm weather returns in the spring, begin turning it again. The compost is ready to use when the pile cools and the material is dark, crumbly and sweet-smelling, like soil."

Complete information about starting a home compost pile is available in "Composting to Reduce the Waste Stream: A Guide to Small-Scale Food and Yard Waste Composting," a 48-page publication featuring easy-to-read charts and guidelines.

Copies of the guide are available for $8 from the Publications Distribution Center, Penn State, College of Agricultural Sciences, 112 Agricultural Administration Building, University Park, PA 16802; Phone 814-865-6713.