Developing a Sense of Humus


Compost happens, says a current bumpersticker.

And it may happen to you. Sooner than you think.

No longer just the pursuit of organic gardeners and environmentalists, composting--the naturally occurring decomposition of yard and kitchen waste collected in backyard piles or bins--is becoming public policy as Southland cities seek to comply with a state law aimed at defusing a looming landfill crisis.

Under the 1989 law, cities are required to reduce landfill trash by 25% by 1995 and 50% by 2000, and a growing number of municipalities see composting as a way to cut waste.

Los Angeles County residents generate and dispose of about 50,000 tons of waste each day, or enough to fill Dodger Stadium every nine days, the Department of Public Works says. About 30% of that waste consists of grass clippings, leaves and other yard materials and could be eliminated if homeowners composted it and used it in their yards, experts believe.

Some Eastern cities virtually ban grass clippings and other yard residue from landfills because it can be easily composted into earthy-smelling humus--"brown gold,” as some gardeners call it--and mixed into flower beds or simply spread under plants.

In the past year, the cities of Glendale, Burbank and Ventura have begun compost programs by sponsoring workshops on the do’s and don’ts of composting and providing compost bins at a reduced price to interested residents. Long Beach and Thousand Oaks will conduct similar programs soon. In Orange County, the cities of Fullerton, Laguna Beach and Newport Beach offer composting classes.


In Glendale, more than 1,000 households are participating in a composting program.

“Our surveys show we’ve already diverted more than 20% of single-family household yard materials and kitchen scraps from landfills,” said Tom Brady, senior planner for Glendale’s integrated waste management section. Glendale hopes to add 1,000 new households each year until about half of its 23,000 single-family homes are participating.

The city of Los Angeles is sponsoring composting workshops throughout the city and will install a demonstration compost site in Griffith Park later this year.

The city had planned to offer compost bins to residents at low cost, but budget constraints forced a change of plans. Residents can buy compost devices at reduced prices through the Los Angeles Conservation Corps (See accompanying story).

Last year, Jerry Christopher was one of hundreds of Santa Monica residents who attended a city-sponsored workshop on composting. Christopher spread the word to his neighbors, who several times a week present him with bags of leftover lettuce leaves and other kitchen scraps for his compost bin.

For the past year Christopher has not thrown any yard trimmings or grass clippings in his trash, which is just what city officials want.

Christopher is a garden hobbyist with a special knack for growing begonias. He admitted that his motivation initially was to produce a top-quality potting soil for his plants. But he’s also pleased that he has significantly reduced the amount of trash generated by his household.

“It’s easy to do, doesn’t take much time and saves me money, because I use the finished compost in place of commercial potting soil,” Christopher said.

Besides the Smith & Hawken Biostack bin he bought at the workshop, Christopher also converted several old plastic trash containers into compost bins by cutting small triangular holes in the sides and bottom of the cans to let in air.

“There are 8,000 single-family houses in Santa Monica and we’re targeting them, plus duplex and triplex owners,” said Jon Root, the city’s waste reduction coordinator. “The people who attended the first workshops were mainly garden hobbyists but now a lot more people are composting.”

Composting is not complicated, although avid composters exchange methods as eagerly as gourmet cooks swap recipes.

“Composting is a simple, natural process that occurs everywhere, even in your refrigerator,” said Joseph M. Keyser, an official with the American Horticultural Society in Alexandria, Va.

“Microorganisms are always at work breaking down biological materials. That slimy lettuce in a forgotten corner of the fridge is the result of anaerobic composting"--a process that occurs without the presence of oxygen.

“When you put the proper ingredients together, add moisture and air, in effect you’re hiring public works organisms that turn the trash into treasure,” said Bill Roley Jr. of Laguna Beach, who conducts composting workshops for cities, including Los Angeles. “It’s the next crucial step in recycling,” he said.

There are two types of composting: “active,” also called hot composting, and “passive” or cold composting.

In active (hot) composting, temperatures between 140 and 160 degrees are generated by the microorganisms that cause the material to break down in the composting process. These temperatures are achieved by carefully monitoring the type of materials placed in the compost pile, adding some water and and making sure that the pile is turned periodically to let in air. It is this turning of the pile that has led to the term active composting.

(A temperature in the compost pile of at least 130 degrees for at least three days is desirable because it kills weed seeds, insect eggs and various plant diseases. It does not cause the pile to ignite.)

Passive, or cold, composting means the waste materials are assembled and the pile is turned just once or twice, or not at all. The material breaks down at a slower rate, and the pile’s internal temperature is lower.

Composting can be as simple and inexpensive as creating a compost pile in an inconspicuous part of your yard or choosing one of the many different composting devices now on the market.

There are advantages and disadvantages to both approaches. Compost piles cost nothing and are easy to make, but they can sprawl, may look unsightly or develop an unpleasant odor if the mix of materials isn’t correct. Rodents can also be a problem.

Commercial composting devices range in price from inexpensive to costly, but are often smaller than the recommended size of 3 feet by 3 feet by 3 feet (27 cubic feet is the minimum size needed for hot composting). They are, however, effective deterrents to vermin.

There’s a growing number of plastic, wood, metal and fiberglass devices available in a variety of shapes and sizes. The consumer can select from open bins, closed bins, stacked bins, tumblers, futuristic-looking geodesic-dome types and a high-tech solar-powered tumbling bin. Prices range from $10 to $550.

Whether you select a commercial bin, make your own or decide to build a pile, the ingredients should consist of a mixture of moist and dry materials. The moist, or green, matter can include grass clippings, weeds, vines, spent flowers and stems, lettuce leaves and other vegetative kitchen scraps and other succulent materials. (Cover kitchen scraps with soil or turn them into the compost to avoid fruit flies.)

These moist materials decompose quickly and provide the sugar and proteins for the microbes digesting the composting material.

The dry, or brown, matter includes dry leaves, small twigs or branches, other garden prunings, straw and shredded paper products such as newspaper, paper towels and cardboard. Because these contain little nitrogen, they decompose slowly.

If your yard contains few trees, consider salvaging leaves from neighbors and storing them until you’re ready to compost them. My neighborhood has century-old camphor trees that shed their leaves each March. I collect the leaves in old garbage cans and store them until I’m ready to add them to my compost pile.

You can expect to have the finished product, also called compost, in from one month to one year, depending on the type of composting process used and the amount of time you spend with your pile.

Mike Graupner, past president of the California Organic Gardening Club, isn’t in a hurry when it comes to composting.

“I stack up my yard wastes in a corner and let it rot,” he said. “I’m interested in the low-effort approach and I don’t need to produce compost in 14 days or even a month.”

Graupner estimates it takes anywhere from six months to a year for his compost pile to yield the finished product, which he spades into his garden two or three times a year. “It takes longer because I don’t turn the pile,” he said. “On my list of things to do, compost turning is on the bottom.”

If you don’t tend a garden and are wondering what to do with the compost you’ve created, put it on top of the soil around shrubs or trees on your property.

If you do garden, the compost can either be spaded into the soil when planting or placed on top of the soil as a mulch.

But it shouldn’t be regarded as a fertilizer substitute.

“Compost usually doesn’t contain enough nutrients to be used as the only food source for plants,” said Sherl Hopkins, the demonstration projects coordinator for the Common Ground Garden Program run by the UC Cooperative Extension.

Hopkins also maintains a test site at Sepulveda Gardens, where he has evaluated 15 commercial composting devices. Hopkins shares an interest with other horticultural experts nationwide who are trying to determine which of the many compost devices now being sold are actually worth the money.

At the American Horticultural Society headquarters, Keyser has established what is probably the largest collection of compost devices in North America. Ninety commercial and homemade compost devices are on display at the National Home Composting Park.

Even though a large number of compost devices exist, the prospective buyer can limit his or her searching to fewer than 10. According to the experts, all have their good and bad points.

One of the most popular is the SoilSaver, a stationary bin that features a door on the bottom for easy removal of finished compost. More than 400,000 are in use in the United States and Canada. It’s popular because of a retail price of about $100 and an attractive appearance. The disadvantage is that it has a relatively small capacity and doesn’t achieve even internal temperatures.

Hopkins favors the Biostack, sold through Smith & Hawken, and through various municipalities at a reduced price, because it’s attractive, works well and with a retail price of less than $100, is one of the more affordable units that permits the composting material to be turned with a minimal effort.

Keyser likes the Biostack for the same reasons. He also reports favorable results with two high-priced devices--the Kemp ComposTumer and the Swisher Tumbler.

The Kemp tumbler is made of metal and retails for about $350. He regards it as a well-engineered machine. One of the newest composting devices is also the most expensive--the Swisher composters, which range in price from $300 to $550 depending on the model. The high-end device features a solar panel to provide the energy to turn the machine.

“It works like a charm,” Keyser said. “It has a timer with eight different options and we’ve set our machine to turn one minute every hour. It achieves an internal temperature of 150 degrees.”

Hopkins has had different results with the solar-powered composter. “It’s difficult to assemble,” he said, “and we haven’t been able to get the timer to work right so the composter hasn’t been turning automatically.”

Keyser also has tested the Tumblebug, a geodesic-looking device with 20 sides that can easily be rolled anywhere in the yard and retails for $189. “Because it’s so easy to move, you can move it to any part of a garden where you have yard residue to compost,” Kaiser said.

He also reports favorable results with the Rubbermaid composter, the Green Magic Tumbler, the Natursoil Cedar Compost Bin and wire bins.

The Rodale Institute in Kutztown, Pa., also has a compost demonstration site with 20 devices on display.

“There is no best composting method--it depends on the situation and the goals of the individual,” Cyane Gresham, Rodale’s compost expert, said in a telephone interview. “A retired person who’s committed to composting can spend more time and effort than a person with limited time, energy or interest.”

Gresham advocates homemade devices. “People confuse composting with compost bins,” she said. “Frequently, the composting process is easier to achieve without a bin because many of them are too small to maintain the temperatures needed for hot composting.”

Keyser favors homemade bins made from wooden pallets. One pallet is placed on the ground and four more are placed upright at each side and fastened together at the corners with rope, wire or chain, to create a bin without a top.

“This method takes just a few minutes and costs nothing,” he said.

(Ask for surplus pallets at grocery stores, warehouses or manufacturing centers. Be sure to ask permission since companies buy pallets for recycling.)

Locally, a compost demonstration site featuring 11 homemade devices and two commercial tumblers is on display to the public at the Fullerton Arboretum at Cal State Fullerton. It was installed in 1990 by members of the California Organic Gardening Club.

Plaques and interpretive signs explain the different approaches, which include wire or wood bins, plastic or metal trash cans, pits, stacked tires, and other types of units.

“This is strictly an educational display to show how these units can work in a backyard,” explained Rico Montenegro, the assistant director. “We encourage people to come here to learn of the different composting approaches and then select one that’s best suited to their landscape and lifestyle.”

Keyser points out that while compost is a natural process that continually occurs, the value of compost devices depends on their uses.

“All compost units will work if a person uses the right composting techniques. But none of them will work if you don’t.”

Reference Books

“The Rodale Book of Composting,” (Rodale Press Books: $14.95 paperback, $21.95 hardcover) “Backyard Composting,” (Harmonious Technologies: $6.95 paperback) “Let It Rot: The Gardener’s Guide to Composting,” (Storey Publishing: $6.95 paperback) “Easy Composting,” (Ortho Books: $8.95 paperback)

Composting Demonstration Sites

Griffith Park Los Angeles Call (800) 773-CITY for site and information about composting workshops. Eldorado Nature Center 7550 E. Spring St. Long Beach (310) 421-9431, Ext. 3415 Arboretum Cal State Fullerton Yorba Linda at Associated Boulevard Fullerton Demonstration site open daily 8 a.m. to 5 p.m. The National Home Composting Park American Horticultural Society 7931 E. Boulevard Drive Alexandria, Va. 22308 (213) 768-5700 Rodale Institute 611 Siegfriedale Road Kutztown, Pa. 19530 (215) 683-6383

Grass Cycling

Experts have devised a method of dealing with grass clippings called grass cycling. New studies show that grass clippings can be left on the lawn. They decompose quickly if cut in small particles, by using mulching mowers.

Conventional rotary mowers can be converted by adding a $15 mulching blade that cuts the grass into fine particles. Grass is 80% water and breaks down very quickly into a source of nitrogen. Contrary to popular thought, leaving grass clippings on lawns doesn’t cause thatch. (Thatch results from shallow watering which encourages the grass roots to remain close to the surface.)

Grass clippings can also be placed around flower beds as a mulch or dried out and added to compost piles or bins.

Compost Offer for L.A. Residents

Residents of the city of Los Angeles can buy the Biostack at the reduced price of $59.50, or the Presto Composter for $13.95, at the Los Angeles Conservation Corps office, 2824 S. Main St., Los Angeles, Calif. 90007. Tax is included in the purchase price.

Bins can also be mailed to residents’ homes. Send check for purchase price, plus $5 home delivery charge to the LACC office. (Checks should be made payable to LACC.) For further information, call (213) 749-3601.


Links in the Compost Chain

Composting is the result of the activities of a chain of organisms, each group breaking down a complex material into a simpler more usable material for its successor in the chain.

1. Green plants use carbon dioxide, water and sunlight to make sugars and other carbon compounds. 2. Animals eat the plants as food, creating waste. Other plants grow old and die leaving behind fallen leaves and flowers as waste. 3. The animal and plant waste then becomes food for smaller creatures such as earthworms and even smaller microorganisms. This final digestion results in the the final production of humus (finished compost). The humus is recycled back into the garden to re-enter the food chain as food for plants.

Getting Started

Composting can be as simple as creating a compost pile in an inconspicuous part of your yard or as high-tech as using one of the many composting devices on the market. Beyond that, it requires equal parts moist and dry materials, water and air. Nature does the rest.

* Materials decompose faster if their mass is small for faster bacterial penetration. Commercial chippers and shredders are available for $400 to $1,500. But similar effects can be obtained by using pruners to cut small branches into one inch pieces or using a rotary lawnmower to crush the surface area. You can also chop twigs into smaller pieces and then bruise their surfaces with a hammer.

* Moisten the pile or unit periodically do it doesn’t dry out. Avoid drenching the pile because that can cause odor.

* Aeration speeds up the process. This involves turning a pile or tumbler, or using a compost tool to stir up the contents of a stationary bin.

* Forget about buying compost activators. Microorganisms are everywhere, ready to digest the biological mass of a compost pile. You can add some dirt or compost from a previous batch to boost the microbe population.

* Compost should be odorless or have just a slight ammonia smell. If the pile develops an offensive odor, correct it by turning and mixing the material to add oxygen.

* Finished compost should be aged a month before you use it in your garden. This insures that the bacterial population is reduced and doesn’t go to work to break down the plants and soil in your garden.

What to Use

GREEN/WET ELEMENTS (Nitrogen Sources) * Yard refuse: Grass clippings, weeds, vines, old flowers, manure. * Kitchen Scraps: Potato peels, vegetable trimmings, citrus rinds, fruit peels, corn cobs (in pieces), crushed eggshells, coffee grounds, tea bags/leaves.

BROWN/DRY ELEMENTS (Carbon Sources) * Dry Leaves: Use as quickly as possible, add horse or cow manure with leaves, shred larger leaves. * Small Twigs, Branches * Straw: Unsurpassed as an aerating medium. * Paper Products: Shred as fine as possible, good source of carbon for your soil (newspapers, paper towels, etc.). * Soil: Not necessary but very valuable. Use thin layers within your heap and a topping of several inches. Helps retain heat and water. Don’t add too much or finished compost will be heavy.

WHAT TO LEAVE OUT * Meat scraps, dairy materials such as cheese, bones, oils and fats. * The waste of dogs, cats and birds are potential carriers of organisms that may cause disease in humans and should not be used in your compost pile.

Choosing a Composter

THE BASIC PILE Simple wire basket. To turn material, lift up cylinder, move to one side, fork material to aerate. Return material to cylinder.

BUILDING YOUR OWN Basic composting setup in three sections. Material is forked from one bin to the next as composting progresses. Side boards are spaced for air penetration and slide out for easy turning, removal of compost. Lids are recommended to keep out animals and rodents.

COMMERCIAL BINS There are many different types of bins you can buy. Pictured here is one of the most popular, the Biostack, sold by Smith and Hawken. Made of plastic, it is one of the more affordable models.