by Colette Slone
You may already be familiar with the worm composting bins at Karma, but for those of you who are not yet acquainted, allow us to formally introduce ourselves.
We are Colette and Mike, Karma members since 2014 and the official Worm Wranglers of Karma’s worm composting (aka vermicomposting) bin!
We started the worm bin 6 years ago when Colette was a Karma staff member. At the time, she needed to find a new home for the composting worms she had been keeping in a community garden she used to be a part of. Our bunch* started when Colette purchased 1 pound of worms from Cathy Nesbitt of Cathy’s Crawly Composters, and since then the worm population has flourished!
The worms we use for our composting bin are red wigglers, or Eisenia foetida. They are a non-native species of earthworm that prefer to seek their food source in the upper layers of soil, as opposed to common earthworms that burrow deeper into the ground. Red wigglers are also extremely well-suited to eating food scraps due to their preference for high nitrogen content. This makes them an ideal worm species for composting.
Every week during the Spring, Summer and Autumn months, we feed the worms from Karma’s organic bin (approximately 30L of food scraps/week) as well as our own personal organics from home. The worms eat a strictly vegetarian diet, and their favourite foods are gourds and melons. To keep the worm bin healthy and odour-free, we aerate the pile every week with a garden fork and add shredded cardboard and egg cartons as the carbon source to maintain a good moisture balance. Occasionally we will add shredded paper and raked leaves. The pile is also home to a diverse and symbiotic population of insects and fungi that contribute to the decomposition process.
Our compost bin has two cells of approximately 64 cubic feet each, and we alternate which cell we actively feed each year. The cell that is not actively fed is left to “cure” during the early Spring and Summer, and any worms in the curing pile are baited and transferred to the active side using onion bags filled with food. They can migrate between the two cells, but we tempt the worms with food as they will happily re-process their own castings for many months.
Once the inactive side has cured, the castings (a.k.a. worm poop!) are sifted to remove larger items like twigs and fruit pits, and the final product looks and smells just like fresh soil. Thanks to our fellow Karma member Jim O’Reilly, we now have two new sifters which made harvesting much more efficient this year. The castings are a highly nutritious supplement for your garden and potted plants. They can be sprinkled on or raked directly into the soil. You can also mix them with water to make a “compost tea”, which you can use to water your plants. During the Summer, we leave the castings in a Rubbermaid bin near the front door for Karma members to help themselves. This year, we produced approximately 189 liters of castings!
We often get asked about what happens to the worms during the winter months. We start the process of putting the worms to bed once the temperature dips below zero for a few consecutive weeks. Since red wigglers are cold-blooded, they rely on their surrounding environment to provide enough warmth and shelter to survive. We do this by building up the pile with lots of food and insulating the bin with cardboard, bagged yard leaves and a tarp cover. As the food breaks down it produces heat, especially in the core of the pile where the worms eventually migrate to. Their eggs can survive sub-zero temperatures for several months so even if some worms do not make it through the winter, their eggs will invariably hatch in the Spring.
Over the last several years, the worms have helped to reduce Karma’s overall waste and produced an abundance of nutritious soil amendment for the benefit of the membership. If you have any questions about the worm composting bin, feel free to catch us while we are working with the worms or send an e-mail to email@example.com. Cathy Nesbitt’s website, www.cathyscomposters.com, is also a fabulous resource for all things worm-related or if you want to purchase your own bunch!
*Bunch, Bed, Clew and Clat (and, even more adorably, Squirm) are all collective nouns for a group of worms 😊