GARDENING : Composting: Garbage In, Garden Out


Before Marie Bouse began composting, her garden was deteriorating.

"Every year my crops produced less and less," says the Santa Ana resident. "Desperate, I decided to try composting. It was the best thing I could do for my soil; it turned my garden around."

Composting is nothing new. It's a process in which leaves, grass and organic materials are allowed to decompose naturally, forming a concentrated soil conditioner that is rich in nutrients. Simply, it turns "garbage" into biologically rich soil.

Compost not only improves the health and vitality of a garden or landscape, but plants require less water and no costly soil amendments, and composting reduces the amount of yard and kitchen waste sent to landfills.

A yearlong study on landfills conducted by the Environmental Studies Institute of Cal State Fullerton found that 50% of Fullerton's waste stream is compost material.

Helping the environment doesn't necessarily mean inconvenience. A properly prepared compost pile is not a smelly pit that attracts rodents, and it's not backbreaking work.

It can be a very simple procedure. First, locate a level out-of-the-way spot that gets some sun. Next, choose one of several types of composting structure to build or buy.

The traditional composting structure is a bin that makes large quantities of compost in a small amount of space. Most experts suggest having at least two or three bins to store, mix and cure soil. Bins can be made from just about any material, such as wood, brick or cinder blocks.

"No matter what you use, each bin should be at least 3-foot-by-3-foot-by-32 inches. If your bin is not at least this size, it will have insufficient volume to hold in heat, which is necessary for decomposition," says Jim McNelly, an environmental consultant and president of Natursoil in St. Cloud, Minn., which makes cedar compost bins.

"When a compost pile is working properly it heats up to 130 to 160 degrees in the center," says Bill Roley, an applied ecologist in Laguna Beach who built Sprout Acres, an ecological house where all waste is composted or recycled. "Creating a compost pile is almost like building a bonfire."

Like fires, compost piles need another critical ingredient: air. Without it, the pile will smell, attract pests and your neighbor's wrath. Compost piles with adequate air circulation don't have odor problems and break down quickly. McNelly advises that any compost bin you buy or build should have 50% air space on all four sides.

Another type of compost setup is a barrel, which makes smaller amounts, but requires even less space than a bin. It is filled then rolled on its side to keep the air circulating.

Bouse uses a large barrel that needs to be turned on a daily basis. "Although it was expensive (about $200), the barrel was worth it," she says. "I load it and then turn it every day. Twice a month it produces just enough compost for my needs."

For an out-of-the-way compost pile that costs nothing and requires little work, a trench can be dug and the materials buried. Earthworms work the compost. This method takes several months to work because there is little air circulation.

A similar, inexpensive method is to dig a hole, place a wire mesh cylinder around it and place materials inside. Secure the wire mesh with chain snaps.

Sheet composting, which layers material on top of the soil, requires no structure and little work. Carrie Teasdale, former head of the Demonstration Organic Garden at the Fullerton Arboretum and Orange County Organic Gardener of the Year in 1987, uses sheet composting to avoid time-consuming turning in her Fullerton garden.

To sped up the process, she lets several chickens turn the soil while they dig for bugs. Within a month, she has a healthy layer of compost on her soil.

Teasdale says plants can be protected from the chickens by using netting around the greenery or putting the chickens in a mobile cage that can be moved to different areas of the garden.

Once the compost structure is in place, you'll need to add two basic ingredients:

Carbon from dry and brown materials, such as straw, alfalfa hay, sawdust, wood chips, nut shells, shredded newspaper, cardboard, dried leaves, twigs and corn stalks.

Nitrogen from generally wet, green and gooey materials, such as fresh grass clippings and garden trimmings, vegetable and fruit scraps, eggshells, tea and coffee grounds, seaweed, bone meal and manure.

"When it comes to manure, stick with horse, rabbit, chicken, sheep or guinea pig, which you can find at stables and through pet clubs," says Teasdale. "Stay away from steer manure sold in stores, because it is often dairy manure, which gets mixed with fly spray, detergents, disinfectants and salts. This all interferes with composting and damages the soil."

Also avoid adding meat, bones, milk products and fat to your pile, because they attract rodents. Dog and cat feces are also not desireable because they can spread disease.

Don't throw in large pieces of anything, because they won't break down. Shred items such as leaves and newspaper. The smaller your compost contents, the more quickly they will decompose.

If you use near equal amounts of carbon and nitrogen materials, you will have a good mix. "Just lean lighter on carbon materials," says Teasdale.

Layer the compost materials, starting at the bottom with bulking agents such as a few branches or wood chips, which will keep the air circulating. McNelly uses an aeration mat, which is a flat perforated pipe that is placed at the base of the pile, allowing air to circulate.

Add the rest of the ingredients in 6-inch deep layers.

Sprinkle water in between layers (another important component of composting), but don't soak it. "You want your compost pile to always be wet like a damp sponge, but never soaking, because too much water will block air flow and cause it to stagnate," says Roley.

McNelly suggests also adding finished compost--no less than 10% and no more than 25% of the material. "This helps you inoculate your pile with the beneficial microorganisms," he says. "On your first batch use rich, dark garden topsoil."

After layering, McNelly suggests poking the pile with a stick in several places to produce air channels.

Within two days, the pile should heat up. Five days to a week later when it cools, it needs to be mixed (or sooner if it begins to smell). Barrels are rolled along the ground or turn; use a pitchfork to mix soil in bins or holes.

Decomposed soil will shrink to more than half its original size, have a sweet, woody odor, will be dark brown in color, and rich and crumbly in texture.

Spread the compost around plants, mix it into the garden and use it in potted plants.

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