high volume in vessel composting
One of our proudest accomplishments this season is the addition of a 4ft diameter by 20ft long high-volume, in-vessel composting machine. But if you told me last March that I’d be sitting here in the fall writing this post I’d have thought you were crazy.
I certainly didn’t wake up one spring morning thinking, “you know what we need…? A giant composting machine!” But here we are! A member of our staff, who is also a co-founder of a local organization called ‘Compost for Good’ saw the material in our wind row compost piles and suggested that we might be good candidates for a machine and that we might even be able to get part of it paid for with a specific grant.
But first, I better explain why simple wind row (pile) composting wasn’t working for us. As a small farm we didn’t have the staff or time to properly manage our compost piles and monitor them for the correct carbon to nitrogen ratio. Our piles were harboring weed seeds and soil borne diseases and we learned that the hard way when I tried to add our homemade compost to some of our beds and unintentionally inoculated them with a sh*t ton of weed seeds. Yikes. So we had pretty much decided that we needed to order in both compost and potting mediums in order to prevent major weeding and disease issues in season.
Why not just work more on improving our wind row system? Several reasons: the first is that it takes someone here about 8+ hours a week to turn a pile and monitor the temps and add new material and bury it back up again. So there’s the labor issue. Second: we have the wildlife issue. As we add more and more food waste to our wind row system to help it achieve higher temps, the critters are drawn to us. A bear and cub(s) visited one night drawn by the yummy smells from our piles. Instead of feasting all night on the food waste, though, they trashed our nearby beehive. Brutal. We also determined that we couldn’t let our dog out any more off leash, because she’d get herself into trouble at the piles, and we worried that rats and other rodents would soon show up. These are all issues that we’d be challenged by if we’d continued with pile composting.
Another thing that got me really excited about the prospect of the large drum composting machine was the idea that if we did it well, and cooked that compost to the FDA recommended 130-140F for at least 3 days, we’d be able to eliminate our reliance on peat-based potting mediums like Pro-Mix and on ordered in compost. The total expense of this project would pay for itself in just 2.5 years- or less given the increasing prices of planting mediums. A bale of ProMix cost us $34 last year. This season it has risen to $54 at our local lumber yard. Oof.
A pile of emptied buckets from food waste collection efforts in front of the hopper to the composting machine. Our shipping container flower cooler is in the background.
The machine has the potential to significantly reduce our operating costs and help us run a more environmentally sustainable farming operation. The major ingredient in potting mediums is peat moss. Peat moss is a great carbon sink if left in the peat bogs. Due to the fact that it is depleted faster than it is regenerated, peat is often classified as a non-renewable resource- and thus the agricultural industries must learn to grow differently. Must.
Have questions about high volume in vessels composting machines? Be sure to check out our podcast, ‘Frost on Flowers’ to learn more and hear our interview with ‘Compost for Good.’ I will also be speaking at the 2022 Association of Specialty Cut Flower Growers conference in Framingham, Massachusetts about our composting machine, plans that are available for these machines, grants to support building or buying them, challenges associated with implementing them, and benefits of bringing this kind of process to your operation. Or share your questions here in the comments and we’ll try to get right back to you.
Best,
