What is a Worm Farm?

A worm farm is a composting method that uses worms to process organic waste into fertilizer. This process is also known as vermiculture, and it's particularly useful for those who wish to have a compost pile but have limited space. A worm farm can be kept in a plastic bin and requires very little room. The worms feed on organic waste like food scraps and their excrement, also called castings, is harvested to use as fertilizer or to enrich the soil in a garden.

Composting is a natural method of creating material to fertilize and enrich the soil without having to rely on any chemicals. A worm farm allows those with limited yard space, or who live in apartments, to participate in this process. The vermiculture process is accelerated by using worms to do the work, and the product has a number of names, such as castings, vermicast, or vermicompost.

The worm farm consists of a bin or series of trays, often made of plastic, with a lid. Some basic bedding material composed of moist newspaper shreds, leaves, and garden soil is placed inside the area where the worms will live, and there are small drain holes in the bottom to allow liquid waste to escape. Many worm farms use a tray to collect the worm's liquid waste, also called worm tea, since it can be a useful liquid fertilizer when diluted with water.

Certain types of worms are better suited for vermiculture than others. Often it's best to purchase the right type of worms to populate the worm farm from a supplier rather than just digging some up from outside. The recommended types are red wigglers or tiger worms, commonly referred to as compost worms. These worms are better for worm farms because they don't burrow as deeply as other types.

Once the worms are in place, the person maintaining the worm farm feeds them with small amounts of organic waste like food scraps, vegetable peels, egg shells, and more. Certain foods like meat, oily items, or highly acidic foods aren't used. The worms will eat the food, processing it into castings by digesting it. Each worm can eat about half of its body weight per day, which is usually used as a feeding guide. The worms will also reproduce and keep the farm populated.

Once the bedding is no longer visible, the castings need to be collected. Many worm farmers harvest the castings by moving all the food to one side of the farm so that the worms will migrate to that area, then removing the castings from the unpopulated area. The castings that are harvested from the worm farm are used to enrich soil, also called soil amendment, or as fertilizer.