Calling all composters: it's cool and it's hot.

Think of composting and worms immediately come to mind, not to mention such unsettling concepts as decay and rot. But get beyond those initial nose-crinkling images and you will discover a process that is both amazing to watch and amazingly easy. And if done right, the only odor will be the sweet, earthy scent of healthy compost.

Compost consists mainly of humus, a dark brown blend of biochemical compounds created when organic materials decompose. It is a complex creation--a living, breathing community of bacteria, fungi, insects and other microorganisms. Applying compost to your garden adds helpful nutrients to the soil, guards against diseases and pests, can enhance soil's ability to hold water and air and may even extend plants' growing season. And processing your own materials keeps them out of landfills.

"We need to stop thinking of what we produce as waste," says Jim McNelly, president of Renewable Carbon Management and inventor of the NaturTech composting system. "Think of 'waste' as resources."

Hot Or Cold, Bin Or Pile?

Getting started with composting is relatively simple, although there are many systems to choose from. "Bins are best," says McNelly. Avoid making freestanding piles, he says, because they're hard to manage and may develop unpleasant odors or attract pests. Bins can be bought (for $15 to $100, depending on the complexity) or built and should have a lid and bottom. Holes about a quarter to a half-inch in size are needed in the bin for aeration.

Next, decide whether you want a hot or cold system. Hot piles work faster, composting materials in about three to four weeks under temperatures that can reach between 120 and 150 degrees Fahrenheit. But these systems require constant aeration and monitoring for moisture, says McNelly. Materials must also be layered in all at once.

Since most people don't have all the necessary materials on hand, it may be easier to compost a cold or passive pile, says Michael Levenston, executive director of City Farmer, a Canada-based urban agriculture organization. Cold composting takes six to eight months and can be built one layer at a time.

For added efficiency, use more than one bin at a time. When one is full, cap it off with about an inch of old compost and begin a new bin--making sure to return periodically to the first one to mix and aerate.

At its simplest, compost is a blend of two kinds of materials: yard waste consisting of leaves and clippings; and kitchen scraps, consisting largely of fruit and vegetables. The secret is finding the right combination of both.

"Composting is a changing, living activity," says Levenston. "It takes time to master." Levenston suggests adding two to three inches of each material at a time. One common mistake of beginners is to fill a bin entirely with grass or leaves, which will smell and not break down well. Mix the materials in your bins about once a month to aerate.

What About Worms and Tea?

If you don't have much yard space, worms can successfully compost for you in indoor or outdoor containers as small as 16 by 19 by 12 inches. Worms can break down food wastes faster than a traditional outdoor system, without smells and pests, says Mary Appelhof, president of compost supply company Flowerfield Enterprises and author of the book Worms Eat My Garbage. Worm waste, known as "castings," adds bacteria that are beneficial to plants.

To set up a worm system, called vermicomposting, first determine how much waste you go through in a week. One pound of worms can process about a half pound of garbage a day. Build of buy a small bin with air holes. Create a layer of bedding with about three to four pounds of damp newspaper (moisture is vital). Finally, add the worms, usually redworms, which are widely available for sale.

A good worm composting system can handle just about any kitchen scraps, Appelhof says, although meat and dairy products can cause odors or attract flies if not covered correctly. "Worm composting requires very little attention, but make sure you don't completely ignore it," Appelhof says.

The latest trend in the ever-growing composting industry is the brewing and sale of compost tea, which is a liquid version of solid compost. Teas can be home-brewed or made commercially.

The tea is a blend of the same microorganisms and nutrients found in compost, and it is used worldwide on plants to help with disease suppression and to reduce the use of fungicides and fertilizers. "It is not a case of either/or. Compost tea is a great supplement to regular compost," says Compost Tea Industry Association (CTIA) Executive Director Cindy Salter. CONTACT: CTIA, [phone], www.composttea.org; Flowerfield Enterprises, [phone], www.wormwoman.com; NaturTech, [phone], www.composter.com.

BECCA MANNING is an E intern.