Vermi-Composting - Region D Recycling & Waste Management District

One composting method utilizes the power of worms in order to recycle food waste to save it from the landfill and produce one of the best-known soil amendments: worm castings. Vermicompost is made from the interaction of earthworms and microorganisms breaking down organic matter. The earthworm’s digestive system breaks down organic material, such as food scraps, which becomes mixed with the worm’s intestinal juices and microflora. The end result is called worm castings, vermicast or worm humus, and is arguably one of the best organic fertilizers and soil conditioners available. Worm castings are essentially worm feces.

As worms move through a worm bin, they consume organic matter (up to one-half their body weight per day!) and deposit it on their bedding as castings. These castings are water-soluble, releasing nutrients slowly to plants while improving soil’s water holding capacity and structure. Castings never burn plants.

Vermicomposting is a fun, low effort way to produce a high-quality soil amendment while preventing useful food scraps from ending up in the landfill, where they emit methane, a harmful greenhouse gas.

How to Set Up a Worm Bin*

*Courtesy “Cornell Composting: Composting in Schools,” https://compost.css.cornell.edu/worms/steps.html

Acquire worms and a bin- Reuse an old dresser drawer or fish tank, build a box out of wood or find/buy a plastic bin. The approximate size is 16″ x 24″ x 8″ or 10 gallons. Make sure the bin is clean by rinsing it with tap water to remove any residues which may be harmful to the worms. For wooden bins, line the bottom and sides with plastic (an old shower curtain or plastic garbage bag works well).

Prepare Bedding- Instead of soil, composting red worms live in moist newspaper bedding. Like soil, newspaper strips provide air, water, and food for the worms.

Using about 50 pages, tear newspaper into 1/2″ to 1″ strips. Avoid using colored print, which may be toxic to the worms.
Place newspaper strips into a large plastic garbage bag or container. Add water until bedding feels like a damp sponge, moist but not dripping. Add dry strips if it gets too wet.

Add the strips to the bin, making sure bedding is fluffy (not packed down) to provide air for the worms. Bin should be 3/4 full of wet newspaper strips.
Sprinkle 2-4 cups of soil in the bin, which introduces beneficial microorganisms. Gritty soil particles also aid in the worms’ digestive process. Potting soil, or soil from outdoors is fine.

3. Add the worms- Before adding the worms, find out how many worms you are starting with. The easiest method is to weigh the worms. If you do not have access to a scale, determine the worms’ volume. The amount of worms is important for knowing how much food to feed them and for record keeping.

Bury food scraps under bedding- Feed the worms fruit and vegetable scraps that would normally be thrown away, such as peels, rinds, cores, etc. Limit the amount of citrus fruits that you place in the bin. NO MEATS, BONES, OILS OR DAIRY PRODUCTS.

Cut or break food scraps into small pieces–the smaller, the better.
Measure the amount of food. Feed worms approximately 3 times their weight per week. Monitor the bin every week to see if the worms are or are not eating the food. Adjust feeding levels accordingly. (If you start with one pound of worms, add 3 pounds of food per week.)
Bury food scraps in the bin. Lift up bedding, add food scraps, then cover food with bedding.

Top bedding- Place a full sheet of dry newspaper on top of the bedding. This will help maintain the moisture balance, keep any possible odors in the bin, and help prevent fruit flies from making a home in the bin. Replace this sheet frequently if fruit flies are present, or if the bin gets too wet.

Cover and choose bin location- Cover the bin with a lid made of plastic, plywood or cloth, but leave the lid ajar so the bin receives some air. If desired, you may drill holes into the bin. Place the bin away from windows and heaters.

Feed, water & fluff- To keep worms happy, feed them about once a week. If bedding dries up, spray with water. (If bedding gets too wet, add dry newspaper strips.) Fluff up bedding once a week so the worms get enough air.

More Resources

Guide to Making an easy, at-home Vermi-Composting* Bin

*Courtesy Master Composters Cornell Cooperative Extension Tompkins County, State of New York