Minnesota gardener Ed Stone has developed a super-simple passive composting system for improving the soil in his permanent beds. I suggest calling it rotational composting, because each bed takes a turn as the primary composting site. Ed’s system combines the benefits of double-dug intensive beds with passive composting. Here’s how it works.
• First, six or more permanent beds are created. Ed uses twelve beds for his diversified vegetable garden.
• Kitchen and garden waste is collected in two or more barrels, bins, or stationary composters. The wet kitchen waste is layered with mulch or leaves to promote decomposition and discourage pests, but the bins are treated as collection points for organic waste, not primary composting sites.
•Each year, one bed is designated as the compost bed. Ed plants potatoes in that plot. When the potatoes come out in August, he begins removing soil along with the potatoes. The soil is loaded into a lawn trailer and hauled to two piles, keeping the top and bottom soil separate. When the bed is excavated to 26 inches, he spreads a layer of the previous topsoil. Then he dumps in the summer’s collection of collected compostables, then more topsoil, then vines, leaves, apples, or whatever autumn brings. When all the previous topsoil is in, he leaves the bed until spring.
•As soon as possible in spring, Ed spreads the winter’s collection of garbage into the bed and covers that with set-aside bottom soil so that the soil layer is at least 10 inches deep. Ed uses the newly renovated bed to grow onions, lettuce and other shallow-rooted crops.
•The next season, the renovated bed is planted with minimal cultivation. It takes four years or more (in MN) for the material in the deepest parts of the bed to rot completely, so you avoid deep digging for a couple of seasons. As time passes you cultivate a bit deeper, so that by the fifth year, you are incorporating the now rotted organic matter into the soil.
•Depending on how many beds you have and how rapidly your soil digests organic matter, you can rotate beds into compost every 5 to 12 years. Shorter intervals would work better in warm, moist climates where the soil seldom freezes and things rot fast.
Ed Stone began working on his system 30 years ago, when the idea of deeply worked, intensive beds captured his interest. “At first I was doing "external" composting, but realized it wasn't a lot more work to put the garbage right into the beds,” Ed says. “You end up with soil that is super stuff, and most plants like sweet corn, potatoes, onions, vines will really grow in it.”