Vermicomposting is a composting technique which uses red worms to accelerate the composting process. Three to six months of vermicomposting will create thick, rich soil to spread on plants and flowerbeds, depending on the container and the amount of household scraps generated. In addition to being an excellent composting tool for regular gardeners, vermicomposting can also be undertaken in small spaces, like city apartments, and it is sometimes used as an educational tool in classrooms.
The process starts with the worm box, which can vary widely in size but should always be shallow and properly aerated, so that the worms can breathe while they eat. The worm box is seeded with moistened bedding materials such as shredded newspaper, peat moss, and corrugated cardboard. A small amount of soil or sand is added to encourage digestion, along with a minimal amount of powdered limestone. Finally, the worms themselves are introduced: most vermicomposting households use Eisenia foetida or Lumbricus rubellas, which are readily available from many garden supply stores.
It is important to start out slowly when vermicomposting, so a small amount of food scraps is introduced at the beginning of the process, to allow the worms to adjust. The amount of food scraps can gradually be increased, although if the box begins to smell or attract flies, the food should be reduced again. A healthy vermicomposting box should have minimal odor, and will start to collect rich, healthy black soil and worm castings after only a few weeks. Most food scraps are usable for vermicomposting, although animal products like bone, flesh, and dairy should be used in minimal amounts. Most vermicompsters keep a small food scrap bucket in the kitchen which is emptied every few days.
After three to six months, the box will be filled with rich, healthy, nutritious soil. In addition, most pathogens which might have been present will be dead after passing through the digestive system of the worms. The soil can be used sparingly on growing plants, to mulch dormant beds, or mixed with water to make a highly nutritious liquid spray. But first, the worm box has to be emptied, so that the worms can be removed and used to start another vermicomposting box.
There are several techniques for emptying a worm box. The most basic involves upending the worm box onto a tarp or another sturdy material and forming the soil into loose piles. The worms will burrow in the piles to avoid light, and the worms can be scooped out of them easily and dropped into a new worm box to start the process all over again.