How to Make Your Own Earthworm Compost Bins

Small plastic storage containers with lids make good bins for worm composting.

Vermicomposting is the process of making a compost, a rich soil amendment, from worm castings. The worms feed on organic kitchen waste to produce the castings, which resemble healthy soil and are loaded with nutrients plants require. Worm composting requires minimal space and can be done indoors, so there is no need for a large outdoor area for a compost pile. Creating your own worm bin is an inexpensive way to begin vermicomposting, as all you need to purchase are the red worms for the bin.

Things You'll Need

• Plastic bin
• Drill
• Bricks
• Window screening
• Newspaper
• Dirt
• Food scraps
• Red worms

Instructions

Bin Assembly

1. Turn a 20-gallon plastic storage bin upside down. Drill eight 1/4-inch holes, equally spaced, along the bottom of the bin to supply drainage. Two rows of four holes is sufficient.

2. Turn the lid of the bin upside down to make a drip tray to catch draining liquid. Set three bricks in the tray and place the bin on top.

3. Cut a piece of window screening 6 inches larger than the bottom of the bin on all sides. Set this in the bin with the overlapping edges pushed against the sides. This prevents compost from slipping through the holes and allows easy harvesting of finished compost.

4. Fill the bin with 6 inches of shredded newspaper. Moisten the newspaper until it is as damp as a wrung out sponge. Use cardboard or damp leaves instead if desired.

5. Add a handful of soil to the bedding to supply the grit worms need for digestion. Place one pound of red worms in the bin. Allow them one week to get adjusted to the bin before you start feeding.

6. Place vegetable and fruit scraps, bread crusts, and eggshells in the worm bin, burying it beneath the newspaper. Feed the worms about 2 to 3 pounds of food a week. If the food disappears more quickly than that, adding more is acceptable.

Compost Harvesting Methods

1. Lay a second layer of mesh, the same size as the first piece, on top of the bedding when most of it has broken down into compost. Place new bedding on top of this second screen and begin adding food.

2. Alternatively, push the compost to one side of the bin. Place fresh bedding in the other half of the bin then place fresh food scraps in this new bedding.

3. Feed the worms, whether in the new bedding above a screen or in the second half of the bin depending on the method used, for two to three weeks. This gives the worms time to migrate to the new feeding area and out of the finished compost.

4. Harvest the compost from the screen-style method by grasping the mesh by the overhanging sides and lift it out. Grasp the excess mesh around the finished compost in the bottom of the bin and lift this out. Replace the netting with the worms and new bedding in the bin and use the finished compost on your plants.

5. Harvest compost from the push-aside method by scooping out the finished compost. Spread the fresher bedding across the entire bottom of the bin once it is emptied of compost. Add additional bedding as necessary to fill it to a 6-inch depth.

Tips & Warnings

• Use red worms, or red wigglers, in the compost bin. They quickly break down the food and don't mind the shallow soil depth. Call a nearby university extension office to find where to purchase them in your area.

• Keep the bedding as damp as wrung out sponge. Add dry bedding if it becomes too moist or add water if it becomes dry.

• Do not feed worms meat, dairy products or greasy food.

• Place a lid loosely on the bin if flies are an issue.

References

• Purdue Extension Office: Household Composting With Worms
• University of Nebraska Extension: Vermicomposting