Sunday, June 21, 2009

Compost Adventures

Huge piles of fresh compost in the three compost areas. Several years ago we designed, and partly built, a waste management system for the Fenway Victory Gardens, where our garden is located. The waste generated by 500 garden plots, each roughly 15'x35', is immense.

Up to that time 'waste management' consisted of paying contractors over $10,000 a year to haul away the garden's 'trash', most of it soft plant materials, a small part of it woody plant matter. And then - get this - the Society would go out and buy expensive truckloads of compost for the gardeners.

The gardens had been crippled for years by incompetent management. They (a chef, then a hairdresser) finally got the boot and a new president was elected who was actually a professional gardener (at the Gardner Museum up the street) and had a clue about managing an organization. She committed to developing a comprehensive waste management program and we signed on to design it. Which violated ny common sense rule of dealing with a nonprofit organization (code word for non-functional).

The focus of our waste management program was to be composting. This required much research into large-scale composting techniques. Eventually we decided on the windrow method, in which soft plant materials are piled up in long narrow lines or rows. I had seen this technique successfully used at Greenleaf Compost, a commercial composting operation adjacent to the Franklin Park Zoo, (one of their sources of raw materials). They did it on a scale that required machinery, our system would be designed it to be managed by hand.

From the start I empahasized, and designed for the fact, that the actual operation of the areas would be as important as the areas themselves. The key was proper management, which would also require the cooperation of all the gardeners.

A basic question was turning the windrows. When you hear the word compost, you almost automatically think turning the pile. But for years I'd made good compost with no turning by simply piling garden debris up in a bin and shoveling finished compost out of the bottom.

I checked the science behind the turn-no turn controversy, such as it is, and it came down to this. Turning is folklore and possibly counterproductive.

Now the rationale behind turning is to aereate the pile, the efficient breakdown of organic matter being an aerobic process, one requiring air. Three problems with that theory.

First. Air adequately infiltrates a pile of mixed soft plant materials (both green, fresh and brown, dry) from 2-feet in any direction. Therefore, no-turn windrows can be made up to 4-feet high.

Second. Soon after turning the oxygen level inside any pile drops back to what it already was. And not much happened in that short time.

Third. Turning disturbs the hot center of the pile where decomposition is actually taking place, like fusion at the the hot center of a burning star. Therefore, it rather than speeding things up, it slows them down.

To be continued ...