Urban Worm Composting Without a Yard

Composting with worms is the ideal method for people who don't have yards. And while some lucky urbanites may have small yards and enough room for traditional outdoor composting, composting with worms can actually be better. Why? Because if you do it correctly, there will be no muss and relatively little fuss.

WHY COMPOST?

Gardening is not the only reason to compost -- reducing landfill waste is another important byproduct. According to the David Suzuki Foundation, if everyone composted fruit and vegetable trimmings, landfill waste would be reduced by 30 percent.

Throwing vegetable trimmings in the garbage doesn't return them to Mother Earth the way throwing them in the garden would. Garbage is dumped in landfills, which are lined with plastic and other materials to pre vent water pollution. The garbage goes on top of the liners and is then compacted, which pushes out the air that is essential for decomposition. Then it's capped with a layer of clay or soil.

The stuff is essentially going to be there forever.

Getting started with composting need not be a formidable task. Fanatics may enjoy tinkering and adding products to speed the process, but the basics are simple -- a source of nitrogen, such as kitchen or fresh yard trimmings; a source of carbon, such as shredded newspaper or dry grass; moisture; and air.

The trick is finding the proper balance of material, but once this has been achieved, a compost pile or bin won't smell bad or attract rodents, fruit flies or other pests.

WORM COMPOSTING

For indoor composting, worms are just about the only way to go, experts say.

For the worm method -- also called "vermicomposting" or "cold composting," because the worms take the place of heat in the decomposition process -- all you need is a covered box with some holes punched into it, shredded newspaper (called bedding), a bit of soil (to aid the worms' digestion), kitchen scraps and worms (a variety called "red worms" or "red wriggler worms").

The worms eat the scraps (which provide nitrogen, a protein source) and the newspaper (which provides carbon, an energy source), digest them and -- compost happens. The worm cast is high in nutrients and beneficial bacteria and has a crumbly structure that improves soil drainage and aeration.

Determine how many worms to buy by estimating how much fruit and vegetable waste you generate. Worms eat their weight in food every day, so a household that generates a half-pound of waste should start with a half-pound of worms (approximately 500), which are available at bait shops and garden centers and through catalogs.

Next, lay down a layer of shredded newspaper moistened to the consistency of a wrung-out sponge. (Worms, which are 90 percent water themselves, need to stay moist to stay alive.) Add a layer of old compost, manure or soil. Then add vegetable and fruit trimmings, coffee grounds, tea bags, bread and grains. Crushed eggshells are acceptable, but they may take a long time to decompose.

Whether you're composting indoor or outdoors, don't add meat, dairy products or bones to your scraps -- they'll attract rodents. Oils and fats also should be avoided.

A well-functioning worm bin will have a sweet, earthy smell. The most common problems are letting the bedding dry out and overloading the bin with more than the worms can eat, which may attract fruit flies. The remedy for flies is to add more bedding and stop adding scraps for a week or two.

The idea of having a box crawling with worms in the kitchen may make some home ecologists just a little nervous. If it's any comfort, worms are unlikely to leave the bin. If they try to escape, it's a clear indication that something's wrong.

The bin can be kept outside, but the worms need to be kept at 68 to 75 degrees to do their work. In hot weather, the bin may need more watering to keep it cool and moist.

Worms, which are hermaphroditic, breed very rapidly. Eight worms will multiply to 1,500 within six months, but there's no need to worry about an overabundance of worms: The population will stabilize itself. If there are more worms than food, the worms will start dying off.

The less squeamish may wish to remove excess worms and give them away or sell them to a local bait shop. Or they could simply be released into the garden, but Nelson says they will probably die, and thereby return to the food chain, because the red wrigglers used in worm composting need manure or rotten food in order to live.

Worms are "low-maintenance pets." You can go on vacation for a month and your worms will be just fine. And kids are intrigued by them.

INFREQUENT HARVEST - HARVESTING YOUR WORM COMPOST

In general, the worm method won't generate a flood of compost. Worms reduce what they eat by 90 percent, so the average one- or two-person bin would be harvested only about twice a year. The compost can then be used in the garden.

There are several methods for separating worms from compost, including simply reaching into the bin and pulling the worms out one by one. If that idea is unappetizing, try pushing the entire contents of the worm bin to one side. On the other side, put fresh, moistened paper and scraps. Eventually the worms will migrate to the new material, leaving the compost on the other side wormless and ready to put in the garden or spread amongst your potted plants.