As much as I love worms and vermicomposting, one of the things I dread most about my job is harvesting compost. No matter what techniques or tools I try, the process is always the same: sorting through dense, rich worm castings and painstakingly removing the worms by hand. At home with my two small blue bins, it’s manageable. But at the much larger scale we operate at the Concordia Greenhouse Project, it’s exhausting, physically draining work that makes you question your life choices. And I can’t delay the process either. The longer I wait to harvest compost, the higher the risk of it going anaerobic. Trust me, you do not want to experience what that smells like.
Luckily, we have one system at the greenhouse that makes my life a lot easier. At the back of our 7th floor space, beside the fish pond and surrounding plants, there is a large green bin on wheels that looks like a small recycling bin. But do not be fooled: this is a Hungry Bin, a vermicomposting system where we have tens of thousands of worms hard at work. In 2023, the Concordia Greenhouse purchased one through a collaboration with ABCompost (at the time part of Zero Waste Concordia) and the Sustainability Action Fund, which has made harvesting compost a lot easier.
What is the Hungry Bin?
The Hungry Bin is a continuous-flow vermicomposting system designed by Ben Bell, a gardener from New Zealand. He wanted to build a vermicomposting system that was less messy and lower maintenance. He initially used discarded curbside bins in his backyard to build a prototype that eventually became what we know as the Hungry Bin today.
What sets it apart from a conventional worm bin is its tapered shape. Food scraps are added to the top, where the worms feed on the organic matter. As they process the waste into worm poop, the castings are pulled downward through the narrowing chamber and accumulate towards the bottom. The tapering shape compresses the castings to the bottom, where it can be released through a removable floor panel and collected using a drip tray that comes with the system. In addition, the Hungry Bin can process up to four pounds of food waste per day, which is much higher than the small vermicomposting kits I have at home.
How Does it Make Harvesting Easier?
A few weeks ago, I harvested compost from the Hungry Bin. I unlatched the bottom panel and the finished compost came out almost entirely on its own. Although I did have to spend a few minutes scraping a little from the top (which got a little messy), I did not have to spend hours separating worms from castings by hand. The worms stay near the top where the fresh food is, so virtually none of them end up in the harvest. The whole process took a fraction of the time.
This works because of the Hungry Bin’s continuous-flow design. Instead of using stacked trays that worms move through, it has one large tapered chamber. The worms naturally stay near the fresh food at the top, while the finished compost collects at the bottom. By the time it’s ready to harvest, there are very few worms in it, making it a much less physically demanding process.
My Final Thoughts
The Hungry Bin is a large-scale vermicomposting system and is definitely not ideal for a small apartment. But for a larger scale operation like ours, it has made a huge difference. Having a system that takes the pain out of harvesting makes everything so much more manageable. Who knows… maybe in the future we’ll get more?