Cornell Waste Management Institute

Garbage: It's For The Worms

(Adapted from Recycling: Mining Resources from Trash,
Cornell Waste Management Institute)
GRADE LEVELS: 4-6, 7-8
CONCEPT: Can worms produce soil from food wastes?
OBJECTIVE: To see biodegradation of food scraps and learn that there can be more productive uses for food garbage than throwing it away.
- plastic 5 gal bucket with small holes drilled in the bottom
  - wooden box, fish tank, or other large container (to build wooden box, see instructions below)
  - red worms
  - bedding (newspaper, leaves, paper bags, and other materials)
  - water
  - food scraps or other organic wastes
If building a container:
  -1 4x8-foot sheet of 1/2-inch exterior plywood
  -1 12-foot length of 2x4 lumber
  -1 16-foot length of 2x4 lumber
  -1/2 pound of 16d galvanized nails
  -2 pounds of 6d galvanized nails
  -2 galvanized door hinges
  -optional: 1 pint of clear varnish or polyurethane
  -optional: plastic sheet for placing under and over the bin
  -1 pound of worms for every 1/2 pound of food wastes produced per day (Worms sold as fishing bait are best. Red worms are available from Flowerfield Enterprises, 10332 Shaver Rd, Kalamazoo, MI 49002; 616-327-0108.)
  -Bedding for worms: moistened shredded newspaper or cardboard, peat moss, or    brown leaves
  -tape measure
  -skill saw or hand saw
  -saw horse
  -long straight-edge or chalk snap line
  -drill with 1/2-inch bit
  -eye and ear protection
  -work gloves
  -optional: paint brush
KEYWORDS: biodegrade, compost
BACKGROUND: Worms in the house? Yuk! But this composting system actually works! The worms stay in the box and eat household scraps, and the box gives off little odor. Worm composting can be done in apartment buildings or other homes with no yard space. You might try it in your school! Many types of existing containers will work if you do not care to build a worm bin.
Shred the bedding needed into a mixing bucket. Fill the container to the top with dry bedding (it takes a long time to shred enough paper). Moisten the bedding materials for the worms by placing it in a 5-gallon bucket and adding enough water to dampen all the materials. Don't worry about getting the bedding material too wet because excess moisture will drain off when it is placed into the composting container. It is a good idea to put wet bedding materials into the bin outdoors and wait until all the water has drained out (up to two hours).
Add about 10 inches of moistened bedding to the bottom of the bin. In go the worms! Leave the lid off for a while and the worms will work down into the bedding away from the light. Then add more bedding until the bin is 3/4 full.
Dig a small hole in the bedding and add your vegetable and food scraps. Then cover the hole with the bedding. Small amounts of meat scraps can be added in the same way. Do not add any potentially hazardous chemicals, or any nonbiodegradable wastes such as glass, metal, or plastic.
Keep your compost moist, but not wet. If flies are a problem, place more bedding materials over the wastes or a sheet of plastic over the bedding, or try placing some flypaper inside the lid. Every three to six months, start a new bin and move the worms into it. If you have built the two-sided bin, move the compost to one side of the bin and add new bedding to the empty half. 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.

Building a Worm Composting Bin
1. Measure and cut the plywood as shown, so you have 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 two 16d nails at each joint.
4.  Nail the 23x42-inch piece of plywood onto the frame with 6d nails every 3 inches.
5.  Cut four 1-foot length 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 length flat against each short end and flush with the top and side edges. Nail the 2x4s in place using 6d nails.
6.  Set the plywood sides up against the base frame so the bottom edges of the 2x4s rest on top of the base frame and 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 3 inches wherever plywood and 2x4s meet.
9.  Drill 12 one-half-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 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, however, 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 to 77 degrees F (13 to 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.
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