TREA's Guide to Worm Composting

Worm composting is the process of using worms and micro-organisms to convert organic waste into a black, earthy-smelling, nutrient enriched soil conditioner. It can be done year-round, indoors. It is an option for both apartment dwellers and home ownders.

The Worms - The best worms to use, because they are such incredible eaters, are called Red Wigglers. They eat and expel their own body weight in one day. However, these worms also eat the bedding in which they live, so 1 lb. of worms will not eat exactly 1 lb. of food waste per day. These worms are native to warmer parts of the globe. Therefore, they prefer temperatures between 13.C and 25.C. They can live quite happily out of doors until the temperatures drop to 4.C. After that they should be taken indoors. For worm sources contact the TREA office.

The Bin - Buy or build a container or use an old dresser drawer, trunk or barrel.

The container should be between 20 and 30 cm. deep and provide 30 cm. squared (1 square foot) of surface area for every pound of food waste per week. Make sure 8 to 10 holes (approximately 1 cm.) are drilled in the bottom bin for drainage. Place a tray underneath to capture the liquid which can be used as liquid fertilizer.

Cover the bin to conserve moisture and provide darkness for the worms. (Keep in mind that most commercial bins come with a lid and do not have drainage holes.)

Light - These worms are very sensitive to light so they will want to remain in the bedding.

The Bedding - Suitable bedding materials include shredded newspaper and cardboard, chopped up straw, sawdust, dried grass clippings, peat moss, compost and aged manure. Vary the bedding in the bin to provide more nutrients for the worms and to create a richer compost. Two handfuls of soil will provide necessary grit for the worms' digestion of food.

Fill the bind 3/4 full with a mixture of damp bedding so that the overall moisture level is like a "wrung out sponge". Worm bedding is usually available at your local garden centre.

The Food Waste - Feed your worms a variety of organic waste. The food which your worms will like the best is your vegetable and food scraps. For example, coffee grounds and filters, apples, lettuce, carrots, banana peels, cruched egg shells, tomatoes, etc.. Try to avoid such things as hair, acidic fruits, meats and dairy products. Bury the food waste by pulling aside some of the bedding, dumping the waste and then covering it up again. This ensures no smell and that fruit flies won't be a bother. Bury successive loads in different locations in the bin.

The Harvest - After 2 1/2 months have passed there should be little or no original bedding visible and the contents will be brown and earthy-looking. It is time to remove some of the finished compost.

The quickest method is to carefully begin moving each layer separating the compost and the uneaten matter. Wait a few minutes between layers to allow the worms to retract deeper into the composter. When you reach the last layer you will notice a large number of worms. At that point you may add your new bedding and start all over again.

Use your finished compost as soil conditioner for house plants, gardens or lawns. Enjoy!

Common Problems

Odors - Unpleasant odors may waft from your bin when it is overloaded with food waste. If this occurs, gently stir up the entire contents to allow more air in. Stop adding food waste until the worms and micro-organisms have broken down what is in the bin. Check the drainage holes to make sure they are not blocked. If the moisture level seems right, the bedding may be too acidic due to a lot of citrus peels and other acidic foods. Adjust by adding crushed egg shells and cutting down on acidic wastes.

Fruit Flies - Discourage fruit flies by always burying the food and not overloading the bin.

Caring for Your Vermicomposter

1. Keep in a cool dark place.
2. Make sure that worms are kept moist (material in composter should feel like a well wrung out sponge.)
3. Do not overfeed - only 1 item every 2 days (chopped up is best).
4. keep the composter covered.
5. When most of the newspaper has been eaten, change the bedding. Remove the worm castings (dirt) and separate the worms out. Put new bedding in the composter: shredded newspaper, 3 handfuls or dirt, and enough water. Put the worms into their new home and feed them.

Have fun!

If you do grow tired of this project, please bury the worms and remaining waste into your garden.

Everything you ever wanted to know about Earthworms... and More!

• There are virtually no indigenous species of worms in Canada. Earthworms died out during the last ice age 50,000 years ago. Present earthworms were brought over from Europe.
• Nineteen species of worms are found "in the wild" in Ontario (of these only 2 are native to North America). Other common names for earthworms include fishing worms, dew worms, manure worms, night crawlers and angle worms.
• Each year Ontario exports over $50 million in worms to the United States.

Habitat and Food Source

• Worms prefer moist loamy soils with organic matter.
• Worms are generally found in the top 12" to 18" of the soil.
• In the spring worms come up to the surface and become active; later in the summer they burrow deeper to avoid dry soil and in the winter migrate below the frost.
• On average there are 250 earth worms in a square meter of soil.
• Earthworms feed on decaying plant and animal matter, bacteria, fungi, algae and protozoa by ingesting soil.

Anatomy and Physiology

• Earthworms do not have lungs. They breath through their skin.
• Worms are hermaphrodites - they have both male and female reproductive organs.
• Eggs are laid in cocoons and hatch in 2 to 3 weeks.
• If a worm is cut in half, only one half survives.

Benefits of Worms to the Soil

• Worms increase availability of Nitrogen, Phosphorous, Potassium and Magnesium for plants and other organisms.
• Secretions from the gizzard act like a cement to hold soil particles together. This improves soil structure and reduces the suceptibility to erosion and compaction of the soil.
• In about 20 years, the earthworms will completely turnover the top 6" of the soil thereby mixing the soil and organic matter.
• Burrowing improves soil aeration and drainage which makes a better environment from plant growth.

For more information

Thames Regional Ecological Association (TREA) for speakers & information on composting call TREA at 672-5991. TREA meets the first Thursday of each month at Grosvenor Lodge, 1017 Western Road, London.