This is part four in a series of seven Field Notes columns by John Marek focusing on sustainable living, community agriculture and food security. These “Summer of Sustainability” columns feature practical advice on growing, harvesting and preserving your own foods, as well as more philosophical essays on life and how we live in the modern world.
Of the hippie-dippy songs of the ’60s and ’70s, perhaps the hippie-dippiest is “Woodstock.” Although written and originally performed by Joni Mitchell, the version with which people are most familiar is by Crosby, Stills, Nash and Young. Punctuated by Neil Young’s staccato guitar and Stephen Stills’ folksy vocals, the song references the famous music festival and builds to the joyful chorus:
We are stardust, we are golden
We are billion-year-old carbon
And we’ve got to get ourselves
Back to the garden
While CSN&Y may not quite have the timeline right, the point about carbon is well-sated. Our planet is a giant carbon processing machine, constantly cycling it through various forms, from microscopic bacteria to giant sequoias to crystalline diamonds to … us.
One way to describe gardening is “extremely focused carbon recycling.” It’s not something we typically think about, but that six-foot-tall cornstalk is composed entirely of a framework of carbon molecules and water, and the bulk of that structure comes directly from the soil. As gardeners, our job is to guide and shape the transformation of carbon from the ground and, to a lesser extent, the air into plants we can consume.
But that’s only the beginning of the cycle. Parts of those plants are eaten by people and animals who excrete the remnants, and the non-edible parts die and decompose, returning their carbon to the soil.
This natural cycle occurred for a long time before humans entered the picture, but once we did we inevitably began fiddling with the process. As early human hunters and gatherers settled down and started agriculture, they quickly learned that repeated plantings on a given plot of land yielded progressively less food. They understood that growing crops depleted the soil of its capability to support plant growth, but they certainly could not have understood why. At some point, however, they discovered that adding amendments like rotting wood, leaf matter and animal dung to the soil seemed to “recharge” it.
Today, we have a much greater understanding of how the process works and a much more focused way of adding carbon and nutrients back into the soil. Most people are familiar with the word “compost,” but depending on your background and experience, you may have different ideas about what it is. I have heard people use the term interchangeably with mulch, soil, garbage, fertilizer and manure, but in reality, compost is none of those things and all of those things.
Compost is organic matter that has been broken down into its essential carbon-rich components by aerobic decomposition. While decomposition is a natural process that takes place on every forest floor, river bank and meadow, composting is the human-assisted version of that process that many gardeners use to provide nutrients for their soil.
Perhaps the biggest misconception about compost is that it is just garbage. While things we typically throw in the trash like food scraps are significant components of home composting, many things we throw away are not compostable, either because they do not decompose (most plastics, metal) or because they add harmful or unwanted microbes or chemicals into the mix. The manure of cows, chickens, pigs and other plant-eating animals, for instance, generates excellent compost, while the waste of dogs, humans and other meat-eaters contains enzymes that interfere with the chemical reactions of the process. Cooking oils and oily food scraps kill the aerobic microbes that power it. Commercial-scale composting operations can use these materials because they constantly monitor the chemistry of their product and adjust the mix, but it is best for home composters to avoid them.
In my book “Ben and the Art of Lawnmower Maintenance,” I mention a primitive form of composting my father learned from his father, who brought it over from the old country. He would dig a garbage pit about two feet wide and three or four feet deep in the middle of the garden and empty all of our kitchen scraps into it. When the fill was six or eight inches from the top, he would cover it with soil and dig another pit a few feet away. I can’t recommend this method, but I won’t deny we had some nice vegetables.
A more common household composting setup utilizes a bin, which can be constructed from wood or concrete blocks, or purchased ready-to-use from the hardware store. Some of the bins are designed to rotate, facilitating turning the compost to increase airflow and mix the components.
A good household compost mix contains half “green matter” – food scraps, garden plant remnants and the like – and half “brown matter” – shredded leaves, paper and wood chips. Compost is ready when it has turned a dark brown color and been reduced into small soil-like particles. The rate of decomposition is determined by several factors, including temperature, moisture and the frequency of turning, but it generally takes several weeks up to a year.
In some communities, an organized compost collection service makes weekly rounds, picking up compostable materials from members who pay a small monthly fee to participate and access the finished compost. This entrepreneurial model can be effective in small towns and rural areas where municipal and county waste management do not offer composting.