Here is a site with several different designs for a home worm farm..
Homemade Worm Bins
BIZY: I'd love to see them...gotta LINK?
Man.. Sorry about that..
http://www.sirinet.net/~gmcowan/worms.htm
OK, here it is again.. Sorry about that..
http://www.sirinet.net/~gmcowan/worms.htm
If you are looking for something on the smaller side I made one of these by the directions here
http://forums.gardenweb.com/forums/load/verm/msg0413312414926.html Basically it is an 18 gallon rubbermaid type tote with a false bottom for airflow. Cheap and easy.
