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Washington State University

Build a Worm Compost Bin

Food wastes can make a smelly mess in your garbage, draw rodents to an open compost pile, and add to water pollution problems when ground in a garbage disposal. So what can you do with food wastes?

You can build a worm bin and let worms eat your food “garbage”! In the process, the worms will provide you with one of the best soil ammendments available – worm castings. Worm castins are very expensive to purchase, but your worms will turn food wastes into an abundance of casting for your plants.

A bin can be built for about $25 using new wood and hardware. Worm bins can also be made from recycled wooden boxes or other containers. Any worm bin must have drainage in the bottom and a tight-fitting lid to keep moisture in and pests out.

A starter batch or worms can be dug out of a friend’s worm bin or from a existing manure or compost pile, or can be purchased at certain locations.

Do Feed Your Worms: Dont Feed Them:
– Vegetable Scraps
– Grains
– Fruit Rinds and Peels
– Breads
– Coffee Grounds, filters
– Tea bags
– Meat
– Fish
– Cheese
– Oily Foods
– Butter
– Pet Wastes


Wood Worm Bin

Materials: Tools:
1 sheet of 1/2″ plywood
1 14″ utility 2 x 4
1 16′ utility 2 x 4
1 lb. 4d galvanized nails
1/4 lb. 16d galvanized nails
2 3″ door hinges
Tape measure, skill saw or rip hand saw, hammer, saw horses, long straight edge or chalk snap line, screw driver, chisel, wood glue and drill with 1/2″ bit.



Measure and cut plywood as indicated in drawing. To make the base, cut the 14′ 2 x 4 into five pieces: two 48″ and three 20″ long. The remaining 12″ piece will be used to make the sides. Nail the 2 x 4s together on edge with 16d nails at each joing as illustrated in the base frame diagram. Nail the plywood base piece onto the 2 x 4 frame using the 4d nails.

To build the box, cut three 12″ pieces from 16′ 2 x 4. Place a one-foot 2 x 4 under the end of each side panel so that the 2 x 4 is flush with the top and side edges of the plywood and nail the boards in place. Nail the side pieces onto the base frame.

To complete the box, nail the ends onto the base and sides. To reinforce the box, place a nail at least every 3 inches wherever plywood and 2 x 4s meet. Drill twelve 1/2″ holes throught the bottom of the box for drainage.

To build the lid, cut the remainder of the 16′ 2 x 4 into two 51″ lengths and two 27″ pieces. Cut lap joints in the corners, then glue and nail the frame together. Center the plywood onto the 2 x 4 frame and nail with 4d nails. Lay the top on the ground with the plywood side touching ground. Attach hinges to the top and back using short screws on the top and the long screw on the back. Position hinges so the screws go through plywood to 2 x 4s.

You can coat your bin with clear polyurethane, varnish, or paint to protect it from weathering.

plans for a worm bin