A BOCA Compost System in a garden on Mercer Island, WA
BOCA: Earth's Mouth ready to eat!
Watching nature's process has been a keen interest of mine as long as I can remember.
Curious how nature managed to plant, sow and grow without tillage of any sort, or so it appeared, fascinated the heck out of me and I wanted to understand just how she did it.
Luckily, I was born into a gardening family in the '50's. I broke my gardening teeth on the Organic Gardening magazines laying around the house. Composting made sense, so I began following the trail of people interested in soil, gardens and growing food & herbs. What a trip!
From Lady Eve Balfour of the British Soil Association to Sir Albert Howard father of organic agriculture to Louis Bromfield's of Malabar Farm and Juliet D' Baircli Levi...all tracks led to a sensible, pragmatic approach to growing food on earth.
Today, finds me well along in my own adventures in gardening, herbs and living life with earth. An unusual twist in the journey came when I accepted the job of Head Gardener for The Herbfarm Restaurant and Willow's Lodge in Woodinville, WA. I had, up until then, been quite content growing on small farms, in tiny gardens and, finally, at my home place RavenCroft Garden, where I still live. While managing a 5 acre high end public hotel garden and a 3000 sq. ft. formal public Kitchen Garden plus a 2 acre row crop farm, during the not-so-great global recession, I gained a great deal of experience finding ways to work with nature, reduce inputs and increase outputs in all 3 sites.
The best idea that came through was the BOCA Compost System. Why BOCA you might ask? It became evident that a garden eating 50 yards of arborist chips a year was a hungry garden. Recycling garden refuse through compost to feed back to the garden meant the system was the mouth we would use to feed the earth. BOCA in Spanish means 'mouth'. The BOCA Compost System was born! No-turning, no-fuss, easy compost...put debris in, take compost out!
BOCA is a simple, rugged, portable framework that is easy to assemble, can be moved whenever desired and can be scaled depending on garden size. A dedicated composter, I wanted to capture and recycle as much garden debris as possible from the gardens, restaurant and farm in my care.
One of 3 BOCA's at Willows Lodge, Woodinville, WA
Sir Albert Howard came up with the calculation that a 5'x5'x5' container proved best for composting. I've found that any uniform size from 3'x3'x3' to 5'x5'x5' works and can be scaled to the garden's output.
The BOCA consists of hog panels with graduated cross wires, cut into 3', 4', or 5' sections and made into 2 bins. These bins can be side-by-side as in the top photo or with a cross piece separating 2 bins as the second photo shows.T-stakes are used as the framework with the hog panel pieces attached to the stakes with zip ties.
Debris is added as it becomes available. The gardens I've tended have supplied the green/brown mix at a workable ratio without much calculation. If there is too much green leaves or straw can be used to buffer the fermentation. What is important is that the garden debris be placed into the BOCA carefully and spread in even layers. Much like one would create a torte.
A raw and finished compost in the BOCA at RavenCroft Garden. Bread seed poppies enjoying fine dining in the decomposed side of the BOCA.
To begin the process, place small woody debris (no larger than 1/2" x 12" ) 8-12" deep on the bottom of the bin. The bins must be placed directly on earth. The first bin is then filled to the very top or just above the top with garden refuse. Leveling and pulling debris forward through the process is important for decomposition to work evenly in the bin. Once the first bin is filled begin loading the second bin. It takes between 6-8 months for the decomposition process to finish. The bin contents will reduce to 1/3 the original amount. Nothing need be added beyond green & brown refuse and water if it is very dry. In the rainy northwest, the bins need cover during the winter to prevent dampening the digestive process.
Composting is a digestive process. Once the BOCA is full, micro-organisms take over and complete the process. In traditional turned compost systems, the turning oxygenates the pile and increases temperatures. The BOCA process is a cool process so a broader spectrum of soil organisms are maintained in the process.
I am teaching a BUILD-A-BOCA workshop May 25th at Square Moon Garden in Carnation, WA where you can learn more about building and operating a BOCA Compost System.