Before human manipulation, all organic things on earth were completely recycled. Plants, animals, and insects lived on the land. When they died, bacteria decomposed them. They returned to the earth and enriched the soil with their remains. No dumps. No landfills. Simply a never-ending cycle of matter reshaping and nurturing itself.
You can speed up the process, take away the odor, and make it more convenient, but even if you do nothing, organic things decompose. And that’s what makes composting such a no-brainer.
Yard waste—responsible for 15 to 30 percent of the annual curbside trash in the United States—is a great place to begin composting.
“I recommend starting with grass clippings and dry leaves,” says Mary Tynes, editor of Master Composter. “Many people begin composting because they’re amazed they can throw food waste outside. But if they don’t know what they’re doing they can attract every stray dog, bear, coyote, and rodent, and odor problems could develop, too. Well, you won’t have any problems with dry leaves and grass.”
The word compost comes from the Latin componere, which means “to put together,” and that’s really what the art of composting is—mixing the right ingredients in the right amounts to create a microorganism-friendly environment. These ingredients are carbon, nitrogen, air, and moisture.
Carbon is the energy source—it does for compost what carbohydrates do for your body. To identify carbons, think of things that burn easily: dry leaves, cornstalks, cardboard, hay.
Nitrogen is the protein source—it breaks down the carbon food and heats things up, essentially cooking the pile and killing most vectors such as weed seeds and pathogens. To identify nitrogen sources, think of things that will smell bad if you ignore them, such as grass clippings, manure, and seaweed.
Many microorganisms require air—especially the most efficient ones, called aerobes. Without enough oxygen, aerobes can’t survive; anaerobes take over and slow down decomposition by as much as 90 percent. To be sure your pile has enough air, you need to turn it. Tynes recommends using a bottomless bin or a circle of fencing. To turn, “pick up the bin, set it next to the pile, then shovel the stuff from the old pile into the bin so that the old pile’s top becomes the new pile’s bottom.” And when you turn the pile, says John Harrison, agricultural waste management specialist for Utah State University Extension, that is the ideal time to add more material.
Microorganisms need moisture, too—ideally the same dampness as a wrung-out sponge. Too little moisture will slow a pile down; too much will force out the air and suffocate the aerobes. Tynes says the best time to water your pile is when you turn it, watering it as you go.
Worms in Your Kitchen?
People who want to compost food but fear drawing wildlife into their yards might consider vermicomposting—using worms to convert organic waste into nutrient-rich humus. When done correctly, vermicomposting is odor-free and can be maintained indoors.
Unlike backyard composting, which relies on a biological process to accelerate decomposition, vermicomposting utilizes a digestive process—worms ingesting and excreting organic material. These are not garden-variety earthworms; they are epigeic (waste-eating) redworms available through gardening stores or the Internet.
“The worms eat all your fruit and vegetable scraps,” says Carolyn Mountel, executive director of the Tomten Institute, which specializes in organic recycling and gardening. “Don’t feed them meat, cheese, or oil, though. That’s not their niche. And don’t overfeed—then they will smell.”
The worms live in a shallow bin you can build or buy. To determine what size you’ll need, collect your organic kitchen waste for a week. Weigh it daily and multiply the average daily weight by two. That’s how many pounds of worms you’ll need. Each pound of worms requires one square foot of space. Make bedding from damp shredded newspaper; food goes on the bedding.
The end result, called worm castings, has a neutral pH and looks like coffee grounds. It’s potent—use only a few teaspoons to fertilize your indoor plants.
For more information, visit Soil Food Web.
If you or anyone in your household is prone to allergies or respiratory ailments, be aware that organic waste collected for your compost bin can produce harmful bacteria and mold.
Researchers at Wageningen University in the Netherlands found accelerated levels of bacterial endotoxins—cell fragments that are released when bacteria die—in households where organic waste, which is moister than mixed garbage, was collected in containers that weren’t emptied for a week or more. Endotoxins can cause coughing, breathlessness, and flu-like symptoms.
If you’re concerned about bacteria and mold levels in your home, be sure to empty organic waste once a week. Also consider storing organic waste in the garage or just outside the back door.
Storing the Pile
Back to your leaves and grass: If you use equal parts of each, you should have a compost pile with a suitable carbon-nitrogen ratio. Keep it damp and turn it—daily if you like, weekly is fine, never will work, too. The more you care for the pile, the faster it will decompose. If it starts to smell, add more leaves.
How to store your compost? You can choose from many types of purpose-specific containers—from plastic bins to backyard tumblers. For beginners, the best option is whatever is cheapest. A simple pile will work fine, but it may spread. The next best choice is to use a bottomless bin that sits on the ground. Buy one, or make your own. Use whatever you have to make a simple container—a circle of chicken wire fencing or four wooden pallets nailed together will do. Just remember that you want to be able to lift the container easily.
And where to keep the compost pile? Use common sense. “You’re trying to attract bugs that eat old wood, so don’t put the pile near your house, fence, or other wood structure,” Tynes says. Put the pile somewhere near a water source. If you live in a dry climate, put it in the shade. If yours is a damp climate, make sure the pile gets sunshine.
Opinions vary greatly on when to spread compost—from “just use it when you need it” to “wait a year after you think the process is done.” Again, use common sense.
Harrison belongs to the use-it-when-you-need-it camp. “Stop adding new material for awhile, and it’ll get static,” he says. “But you may need to put it through a sieve and strain it.” One potential drawback to this approach—especially if food is used—is that when compost isn’t done, it will attract bugs to wherever it’s spread. If you see bugs crawling in your pile, it isn’t ready.
Be conservative when the compost will be used for a vegetable or herb garden. “The theory is that the heat of a pile will kill pathogens,” Tynes says, “but a lot of people aren’t as good at tending their compost as they plan to be.” A potential problem may be grass that might have been treated with ant poison or weed killers. “You can put compost made with that back onto your lawn,” she says, “but be careful with compost that goes around edible plants.”
To apply finished compost to a lawn, broadcast it about a quarter-inch deep. You can also use it for potted plants, one part compost to two parts soil.
Taking the Next Step
Once you’ve mastered the leaf and grass pile, there are many ways to make composting more interesting. You can buy thermometers to measure the heat and indicate the best times to turn it. You can buy special sieves for your finished product. You can start adding food, newspaper, manure, even stale beer. There is an abundance of very specific information available on how to improve the composting process—from monitoring pH levels to exact calculations of carbon-nitrogen ratios.
Just remember that no matter what, compost happens. Stinky garbage will become sweet-smelling soil. As Tynes says, “The more you work with compost, the more you understand the brilliance of the plan.”