Vermicomposting bins vary drastically depending on the system an individual composter wishes to create.

Small scale

Small scale systems offer a wide variety of bins. Often, small-scale composters build their own bins. Companies also offer commercial models for sale. Commonly, bins are built out of old plastic containers, wood, Styrofoam containers, or metal containers.

Some materials are less desirable than others in bin construction. Styrofoam is believed to release toxins into the earthworms' environment. Metal containers often conduct heat too readily, are prone to rusting, and may release heavy metals into compost.

The design of a small bin usually depends on where an individual wishes to store the bin and how they wish to feed the worms. All bins in general have holes for airflow in the sides and some form of drainage, either holes in the bottom to drain into a collection tray or an actual spout that can be opened or closed to allow drainage. Plastic bins generally require more drainage than wooden ones because they are non absorbent. Regardless of the material used to build the bin, most small bins can be grouped into three categories:

• Non-Continuous ? A non-continuous bin is an undivided container. A layer of bedding materials is placed in the bin, lining the bottom. Worms are added and organic matter for composting is added in a layer above the bedding. Another layer is added on top of the organic matter and the worms will start to compost the organic matter and bedding. This type of bin is often used because they are small in size and easy to build. They are relatively difficult to harvest because all the materials and worms must be emptied out when harvesting.
• Continuous Vertical Flow ? Continuous flow bins are a series of trays stacked vertically. The bottom-most tray is filled first, in a similar fashion to any other bin, but is not harvested when it is full. Instead, a thick layer of bedding is added on top and the tray above is used for adding organic material. The idea is that the worms will finish composting the bottom tray and then migrate to the one above. When a sufficient number of worms have migrated the bottom tray can be collected and should be relatively free of worms. These bins provide an easier method of harvesting.
• Continuous Horizontal Flow ? A continuous horizontal flow bin is another bin that relies on the earthworm's habit of migrating towards a food source in order to ease the process of harvesting. The bin is usually constructed to be similar to a non-continuous bin but twice as long (horizontally). The bin is divided in half, usually by a large gauge screen of chicken wire. Only one side is used initially. When that half becomes full, the other half is filled with bedding and organic matter. In time, the worms will migrate to the side with the food and the compost can be collected. These bins are larger than a non-continuous system but are still small enough to be used indoors, with the added bonus of being easier to harvest.