Tag Archives: Food Scraps

Nature’s composters – worms

Earthworms are nature’s digesters. Aristotle said earthworms were the soils entrails. Charles Darwin surmised that most all of the fertile soil on earth must have passed through the gut of an earthworm.

Worm Biology

Instead of teeth, earthworms have a gizzard like a chicken that grinds the soil and organic matter that they consume. They eat the soil microorganisms that live in and on the soil and organic matter.

Worm excrement is commonly called worm casts or castings. These soil clusters are glued together when excreted by the earthworm and are quite resistant to erosive forces. Their castings contain many more microorganisms than their food sources because their intestines inoculate the casts with microorganisms.

Worms and Soil

Earthworms are part of a host of organisms that decompose organic matter in the soil. As earthworms digest the microorganisms and organic matter in soil, the form of nutrients is changed as materials pass through the earthworm’s gut. Thus, worm casts are richer than the surrounding soil, containing nutrients changed into forms that are more available to plants. For example, one study found that in a sample of soil with 4% organic matter, worm casts contained 246 pounds of nitrogen per 1000 square feet while the surrounding soil contained 161 pounds of nitrogen per 1000 square feet (Source: ATTRA, Sustainable Soil Systems)

By increasing the organic matter content, soil porosity and aggregation, earthworms can greatly increase the water-holding capacity of soils.

Earth worms are nature’s digesters. Aristotle said earth worms were the soils entrails. Charles Darwin surmised that most all of the fertile soil on earth must have passed through the gut of an earthworm.

Vermicomposting or Worm Composting

With very little investment you can put earthworms to work turning kitchen scraps into nature’s best fertilizer for your garden.

You can compost with worms indoors or out; it’s perfect for apartment and house dwellers or at the office.

All you have to do is put some red wiggler worms (not local earth worms) into a bin with some moist bedding. Then add your food scraps (like apple cores and vegetable peelings). The worms will eat the scraps and produce great compost for your house plants, garden or flowerbeds.

The worms work quickly at temperatures ranging from 15 to 25 degrees Celsius, consuming up to half their body weight in food each day.  They won’t survive freezing temperatures, so you will have to bring them indoors during winter.

Mary Appelhof, author of “Worms Eat My Garbage” recommends two pounds of worms — about 2,000 wigglers — for every pound per day of food waste. To figure out how much food waste your household generates, monitor it for a week and divide by seven. Other vermiculture experts advise starting out with a smaller amount of worms and reducing the amount of food scraps you compost until worm population grows. Worms can double their populations every 90 days.

The Bin

You can purchase a worm bin or make one. Whether you choose a plastic, wooden or glass container to use as a worm bin is a matter of personal preference based primarily on what is available. The size of your bin depends on how much food you’ll be adding. A bin should have about one square foot of surface area for each ½ kilogram (1 pound) of food added each week.

You can make your own worm bin by repurposing a “Rubbermaid®” type tub and turn it into a composting bin.

The Bedding

Proper bedding is important to maintain your worms’ health. Shredded newspaper, potting soil (without chemicals), straw, fall leaves or a combination of these will be fine.

Fill your bin almost to the top with loose bedding then sprinkle water on it until it’s as wet as a wrung out sponge. It should form a mud ball when a handful is squeezed.

Feeding Worms

Feed your worms food scraps such as fruit and vegetable peels, pulverized egg shells, tea bags and coffee grounds. Avoid meat scraps, bones, fish, leftover dairy products and oily foods since these will make your compost pile smell as well as attract flies and rodents. Experts are divided on whether pasta and grains should be tossed into the compost or thrown away in regular garbage. Your best bet is to experiment and let your worms tell you what they’ll eat or won’t eat.

Bury your scraps into a different part of the bedding each week to evenly distribute the food for the worms and to discourage flies. The smaller you cut the scraps, the faster they will disappear.


After 3 to 6 months, the worms will have digested not just your food, but their bedding as well. What is left over is called Vermicompost and it is an excellent additive to your house plants or flower beds. There are several ways to harvest worm compost.

Trouble Shooting

Fruit Flies

One of the most common problems with bins are fruit flies. Fortunately, they don’t bite and they’re easy to deal with.

  • Chop banana peels.
  • Keep scraps covered with a few inches of bedding or castings.
  • Freeze scraps overnight before adding them to the bin.

Fungus Gnats

The other small flying insect which can invade your bin is more bothersome because it can also survive in your house plants.   An added challenge is that whatever you do to kill these pests may kill many of your beneficial decomposers.  Isolate your bin and harvest.

Other Creatures

Many other small creatures may share your bin with the worms. Most of them are helpful and rarely cause problems. Only centipedes, which will eat your worms, pose any threat to your bin.


If your bin smells bad, it probably has too much food, water, or the wrong types of food inside. To eliminate odours, remove excess or inappropriate food and add fresh bedding. You might also leave the lid off to allow for evaporation.

A cautionary tale

Invasive Alien Species and Forests: If you live in the eastern half of Canada, every earthworm you have ever seen in your garden is technically an invasive alien species. Although there are over 100 species of native North American worms, they’re only indigenous to “un-glaciated” areas such as the Pacific Northwest (British Colombia’s hemlock forests, for instance). Elsewhere on the continent, earthworms were killed off during the last “Ice Age” (the Wisconsin Glacial Episode), and for the past 11,000 years, our northern forests have evolved without them. There are now over 15 species of Eurasian worms burrowing their way through our Canadian soil.

The problem is while our gardens benefit from the swift conversion of organic material, forest run on a slower timeline. Earthworms gorge on forest floor’s rich leaf litter, leaving the underlying mineral subsoil exposed, and effectively wiping out tree seedlings, and ferns who suddenly find themselves without root zone.The most dramatic destruction of habitat has been seen in the hardwood forests of the Great Lakes-St. Lawrence River Basin.

We can help this problem from spreading further. Individuals fishing can stop dumping leftover earthworm bait and gardeners living near forested areas can flash-freeze finished compost for one week before spreading it.  Gardeners can stop dumping green waste in forests.

Cleopatra is said to have made a royal decree that the removal of earthworms from Egypt was punishable by death for fear of offending the god of fertility.