At the very end of our process when the compost has cooked and cured we run it through a trommel screen to screen the “fines” out from the “overs”. The fines consist of any compost that can pass through the screen size and is generally small and soil-like. The overs consist of anything that can’t pass through the screen and generally includes the large, woody material and any plastics or contamination. The fines are then sold as compost and the overs are left to find a home. Typically, overs are re-run through the composting process or used as a biofilter on active windrows. In our case, we have been working with Mosier Valley Organics to use the overs as a nutrient-rich mulch. Overs have been completely composted and are covered in good micro & macro-nutrients while also having lots of fines tucked in between the wood chips.
The thinking from Silas at MVO was that overs could be a perfect mulch for his orchard trees. The woody material would serve as weed suppression while the fines will supply the trees with nutrients and help with water retention (thus reducing the amount of water he needs to apply to trees). All-in-all we think it’s pretty innovating thinking and are excited to see the results. So far the MVO crew has applied overs to a few rows of trees and they’re looking pretty happy.
Big thanks to Silas, Kirk, and Maya at MVO for trying out the overs and for producing delectable food and fruit for the gorge community.