Building and Maintaining
Worm Compost Bins


building materials

-Building Directions-

  1. Measure and cut the plywood as shown above, to make one 24x42-inch top, one 23x42-inch base, two 16x24-inch ends, and two 16x42-inch sides
  2. Cut the 12-foot length of 2x4 lumber into five pieces: two 39-inch pieces, two 23-inch pieces, and one 20-inch piece.
  3. Lay the five pieces on edge on a flat surface to form a rectangle with the long pieces on the inside and the 20-inch length centered parallel to the ends. Nail the pieces together with the two 16d nails at each joint.
  4. Nail the 23x42-inch piece of plywood onto the frame with 6d nails every three inches.
  5. Cut four 1-foot lengths from the 16-foot length of 2x4 lumber. (Save the remaining 12-foot piece). Take the two 16x42-inch pieces of plywood and place a 1-foot flat against each short end and flush with the top and side edges. Nail the 2x4's in place using 6d nails.
  6. Set the plywood sides up against the base frame so that the bottom edges of the plywood sides overlap the base frame. Nail the plywood sides to the base frame using 6d nails.
  7. To complete the box, nail the 16x24-inch pieces of plywood onto the base and sides at each end.
  8. To reinforce the box, make sure a nail is staggered at least every three inches wherever plywood and 2x4's meet.
  9. Drill 12 1/2-inch holes through the plywood bottom of the box for drainage.
  10. To build the frame for the lid, cut the remaining 12-foot piece of the 16-foot length of 2x4 lumber into two 45-inch pieces and two 20-inch pieces. Lay the pieces flat to form a rectangle, with the short pieces on the inside.
  11. Lay the 24x42-inch piece of plywood on top of the lid frame so the plywood is 1 1/2 inches inside all the edges of the frame. Nail the plywood onto the frame with 6d nails.
  12. Attach the hinges to the inside of the back of the box at each end (on the 2x4) and the corresponding undersides of the back edge of the lid frame, so the lid stands upright when opened.
  13. The unfinished box should last for at least five years; finishing the box with varnish or polyurethane will protect the wood and prolong the life of the box. Two coats of varnish with a light sanding between coats should be sufficient.
  14. Find a good location for the box. It can be placed anywhere as long as the temperature is more than 50 degrees F (10 degrees C). The most productive temperature is 55-77 degrees F (13-25 degrees C). Garages, basements, and kitchens are all possibilities as well as the outdoors in warm weather (not in direct sunlight). Make sure to place the box where it is convenient for you to use. It is wise to place a plastic sheet under the box.
    adding the worms.
    Moisten the bedding material for the worms by placing it in a 5-gallon bucket and adding enough water to dampen all material. Don't worry about getting the bedding material too wet because the excess moisture will drain off when it is placed in the compost bin. It is a good idea to put wet bedding material into the bin outdoors and wait until all the water has drained out (1-2 hours).

    Add about 8 inches of moistened bedding to the bottom of one side of the bin. Put in the worms. Leave the lid off for a while and the worms will work down into the bedding away from the light.

    adding your wastes.
    Dig a small hole in the bedding and add your vegetable and fruit scraps. Cover the hole with bedding. Small amounts of meat can be added in the same way. Do not add anything inorganic or potentially hazardous material such as chemicals, glass, metal, or plastic.

    maintaining your compost pile.
    Keep your pile moist, but not wet. If flies are a problem, place more bedding material over the wastes. Every three to six months, move the compost to one side of the bin and add new bedding to the empty side. At this time, add food wastes to the new bedding only. Within one month, the worms will crawl over to the new bedding and the finished compost on the old side can be harvested. Then add new bedding to the old side.
    For more information, please see The Worm Woman's Web Site by Mary Appelhof.