Vermicomposting, or vermiculture, enlists a small army of worms to turn organic plant wastes (food parings, rinds, peels and lawn clippings, for instance) into rich plant food, known as "worm castings." The practice is well known to home gardeners but is also done on the industrial and civic scale.
Humble as it may be, the worm has a long and storied history on this planet. From ancient Egypt (when Cleopatra declared the worm sacred for its essential contribution to the fertility of the Nile delta) to the teachings of Aristotle (who called worms "the intestines of the earth"), the wigglers' contribution has not gone unnoticed. Charles Darwin himself studied worms for almost 40 years, eventually stating that worms could be counted among the most influential animals in world history.
There are three kinds of vermicomposting bins used for the process: noncontinuous, continuous vertical flow, and continuous horizontal flow. Noncontinuous bins are compact enough to work well for small-space gardeners and urban folks, but they're harder to harvest. Continuous vertical flow bins are a series of stacked trays; the worms move from one to the next as they finish their work, and the harvester simply removes the finished tray. Similarly, continuous horizontal flow bins are much like the vertical except that they're clicked together side-to-side instead of stacked.
It takes about six to nine months to get a home vermicomposting system up and running at optimal levels (approximately a full tray of castings if using a continuous vertical flow bin). Once established, the worms in the system can be expected to process between 5 to 8 pounds of scraps in a month's time, but it takes time to build the worm population to that point (about 10,000 worms).
Properly tended, a worm bin will become something of a mini-farm, dedicated to the process of decomposition. You may notice multiple different kinds of larvae, pillbugs, fungi, molds, mites and perhaps some flies. There's no need to eliminate these non-worm elements from the worm bin unless they're intolerable where your bin is set up.
Contrary to popular belief, vermicomposting isn't necessarily a "stinky" process. It's much less so than regular composting, because the worms do such a quick job breaking down the rotting material. Keeping a worm bin stink-free is as easy as avoiding tossing animal products into the bin and striking a balance between nitrogen-rich "green" compostables and nitrogen-neutralizing "brown" compostables. Worm bins, properly tended in this way, can live peacefully indoors -- even in the kitchen. Castings themselves are completely odorless.
One benefit of vermicomposting is the obvious benefit of keeping decaying wastes out of the landfills. In addition, passage through the worms' digestive tracts changes the very makeup of the material, changing those nutrients into a form that is much more bio-available to the plants it's applied to. Bins are cheap to make and maintain, and the fertilizer that the worms produce is perfectly organic and much richer than store-bought fertilizer.