In the Garden Articles

Celebrate Earth Day: Compost Now

by Joan S. Bolton

A traditional compost bin

Do worms eat your garbage?

Before you squirm at the prospect, consider that feeding your waste to worms and other insects and microorganisms beats transporting it to a landfill. The end result is compost, a terrific soil amendment in the garden. And what better way to celebrate Earth Day, than to return good things to the earth?

What Compost Is

All living matter decomposes eventually -- whether it's scraps from your table or trimmings from your garden. The resulting, broken-down matter, teeming with beneficial microbes, improves soil structure and fertility in the garden.

Set up a composting system and you'll speed up the process. You'll see results within a few months to a year, rather than sometime after your own lifetime.

"Compost solves a lot of problems that people have with their soil," said Jeff Simeon, a program specialist with the Santa Barbara County Public Works Department. He's in charge of backyard composting, school recycling, coastal cleanup days and similar programs.

"You'll be actively increasing the organic content in your soil," he said. "Compost increases the friability of the soil, increases water flow through clay soils and increases water retention in sandy soils."

To start composting, most gardeners toss yard clippings and food scraps into a pile or a vented bin. A few tightly seal the remains. Apartment and condo dwellers who don't produce yard clippings may tend red worms that work through their leftovers.

Piles and Bins

This traditional method, called aerobic composting, combines air, water and a mix of brown and green waste. You can use a bin, typically composed of recycled plastic panels and a lid, or build your own with four 4"x4" redwood posts, slats and a tarp.

Store-bought bins measure about 3 feet wide, stand about 3 feet tall and hold about a cubic yard of material. Home-built bins may be larger.

For results fast, fill the entire bin at once.

A good mix is three parts carbon to two parts nitrogen. For carbon, think brown or dried material, such as leaves, twigs, straw and sawdust. For nitrogen, think green, or lawn clippings and fresh yard trimmings.

Kitchen scraps, ready to go.

Vegetable scraps are green, too, while stale bread and leftover pasta are brown.

I keep an inexpensive, stainless steel pot with a tight-fitting lid next to my kitchen sink to collect indoor scraps. However, I don't save meat, fat or dairy products, which can smell bad and attract rodents. More important, home compost piles don't get hot enough to kill pathogens that might contaminate the mix.

Chop, clip, chip or shred your material, whether from indoors or out, into pieces an inch thick or smaller, to hasten the process. Alternate layers of green and brown as you fill the bin, dampening the layers with water as you go.

The pile should warm up within a few days, which indicates that the microbes have kicked into gear. Don't worry about where they came from -- they're already there.

If your pile does not heat up, it may not have enough nitrogen: mix in more green clippings, seaweed or blood meal. If the pile looks slimy and smells like ammonia, it has too much nitrogen: turn over the contents and blend in dry leaves or other brown materials.

Nearly finished compost

Water and turn your pile once a week. When most of the mix has turned a rich, brown color and smells earthy and fresh, it's ready. Not all the contents will have decomposed completely. Because you're not a commercial operation, your compost is not likely to have a refined, uniform appearance.

"Don't think you're going to get pristine, market-ready compost," Simeon noted.

But that's fine. Sift out any material that's impossibly large and save it for your next batch. What has decomposed fully is humus, which will improve your soil texture. The smaller, partially decomposed material will release nutrients as it continues to break down in your garden.

The Lazy Man's Method

Dueling bins

If this seems like too much trouble -- or if you intend to add to your pile bit by bit, rather than all at once -- consider the lazy way that I make compost.

Set up two bins. In the first, dump a few inches of potting soil, followed by some loose yard trimmings. Add kitchen scraps at will, covering them each time. Toss in any clippings that come along, both green and brown. If you add wet, green lawn clippings, though, be sure to stir them with the contents below. Otherwise, you'll end up with a thick, slimy mat.

I also pour in a few handfuls of potting soil every so often, and water and turn the pile every few weeks.

Early on, there's not enough volume to heat the pile. But decomposition still chugs forward, albeit slowly. The compost should be ready in about a year.

While that may seem like an impossibly long time, the nifty thing is that you're still able to divert a tremendous amount of green waste in the meantime.

"It's amazing that the containers can hold as much as they do," Simeon said. "That makes it even better in terms of keeping waste out of the landfill. Once in a landfill, the material does degrade, but much more slowly, and it takes up more space. At Tajiguas, there will be materials that are compostable that will not compost because of the conditions... Things do eventually degrade, it's just a question of the time scale. Compost can form in 3 months or less if you're really active with it. Or a thousand years, if it's some arid climate."

In the meantime, there's that second bin. When the first fills up mid-year, I snag a few shovelfuls of decomposing material from the bottom and spread it on the bottom of the second bin. By the time the second bin is full, the finished compost in the first is ready to go into the garden, and the cycle continues.

Anaerobic Composting

If you produce lots of green kitchen scraps and lawn clippings, but next to no brown material, consider anaerobic composting.

As opposed to aerobic bacteria, which require oxygen, anaerobic bacteria do their work without oxygen. A typical system consists of a bottomless round bin the size of a rain barrel, buried 6 to 12 inches. Fill it with green material, add enough water to form a mucky swamp, then tighten the lid. Once or twice a week, top off with more water.

I'll issue a disclaimer here -- I've only seen this system once, and it was a foul-smelling disaster.

Simeon said he did not have much experience either, although he added, "If you're producing food waste, it's a good route to go."

The problems I see are two-fold: the process can be incredibly slow, and the smell is beyond belief.

Stu Campbell, author of the landmark "Let It Rot!" writes that anaerobic composting can be up to 90 percent slower than aerobic composting.

He also notes, "The anaerobe can never digest organic matter as completely as can his oxygen-using counterpart. Along with the good things he manages to put out, he also produces a lot of useless organic acids and amines (Ammonia-like substances) which are smelly, contain unavailable nitrogen, and, in some cases, are toxic to plants."

Enough said.

Vermiculture

The good news, though, is that if you produce a lot of food waste, red worms may be the perfect solution.

These wriggly guys thrive on table scraps. Outfit a bin or crate, and they will keep your food waste out of landfills and generate worm castings -- earthworm poop, really -- which is a surprisingly wonderful soil amendment.

You can buy a worm bin, which is a two-layer rectangular box with holes drilled in the middle level so that the castings drop to the bottom. Or you can build your own.

Provide nesting material composed of leaf mold, shredded cardboard or shredded newsprint, a sprinkling of dampened peat moss, several handfuls of soil and lots of yummy leftovers. As with outdoor composting, stay away from meat, bones and dairy products.

Be sure to use red worms (Eisenia foetida or Lubricus rubellus), which you'll have to buy. Both are debris lovers that thrive in leaf litter in nature. The common earthworms that we find in Central Coast gardens -- field worms and night crawlers -- dig long horizontal and vertical tunnels, and require far more space than a bin can provide.

Place your bin on a protected patio or under your kitchen sink, where temperatures don't fluctuate beyond 55 to 75 degrees.

# # #

Composting Workshops and More

Want to learn more about composting?

Attend a free workshop by the county's Public Works department.

"Organic materials that can still have an active use, adding nutrients to the soil and not getting into the landfill, is a good thing," said Jeff Simeon, program specialist. "It helps us divert some waste from the landfill. It's a way the homeowner can actively recycle and compost in the back yard."

Workshops will be held:

May 2, 10:30 a.m. - noon, Santa Maria Valley Sustainable Garden, 624 W. Foster Rd., Orcutt

May 16, 10 - 11:30 a.m., Solvang Branch Library lawn, 1745 Mission Dr., Solvang

June 6, 10 - 11:30 a.m., Santa Barbara City College, Lifescape Garden, East Campus, 721 Cliff Dr., Santa Barbara

Compost bins are available for $40 at the North County Public Works Building, 620 W. Foster Rd., Orcutt, and South Coast Recycling and Transfer Station, 4430 Calle Real, Santa Barbara.

An updated booklet, "The Answer is Backyard Composting and Yard Waste Reduction," is available online at lessismore.org. Questions may be directed to Simeon at 882-3618 or jsimeon@cosbpw.net.

# # #