There are many different types of wormery on the market and several different means of working (or not, as the case may be!) The following advice sheets are designed to help you choose the right one if it is your first time or to offer advice on how to improve on a “difficult” one if you already own one and are struggling.
The simple box
A simple box is a very good starting point, ideally it would be of wood but often plastic can be more practical, to be efficient it would need to be no smaller than the kerbside recycling box as supplied by your local council, with a lid.The main considerations for any wormery are surface area and a really good air supply, drainage holes in the base will be necessary, particularly with a plastic box.
The single tray
This the next step up from a box, constructed from plastics, it consists of a base box with a “working” tray that sits just inside the base box, the lower box acts as a drip catcher and usually has a spout or tap to drain off any excess liquid that may be produced. The working tray has a perforated bottom to allow any excess moisture to drain away.
The multiple tray
The multiple tray wormery is the next step up from the single tray, the idea is that when the first tray is full a second tray with a perforated base is placed on top of the full one and waste is added to this second tray, the theory being that the worms will move from the first (now full) tray, via the perforations up into the second tray to continue feeding. There are also systems with 3 or more trays. An example of this system is the Worm Cafe as sold on this web site http://www.wormsdirectuk.co.uk/product/worm-cafe-kit/
The Flow Through
The flow through system is considered to be the Rolls Royce of worm composting systems, it is usually based on a wooden box but the bottom is replaced by a riddle mechanism, this mechanism, usually produced out of galvanized steel allows the operator to riddle the finished worm casts/compost from the bottom, settling the contents and creating more space for adding waste feed, the theory being a continuous cycle of feeding, riddling and feeding removing the need to separate worms and compost when the bin is full.