Gardening For Good: Composting at Home

You may be thinking that composting involves a pile somewhere out in the backyard where you dump lawn clippings, leaves, spent flower arrangements, and the shucked outer layers of summer corn. And you would be right! But composting is so much more and is increasingly being recognized as a powerful tool to manage food waste, capture carbon in an effort to offset climate change, and generate a powerful soil organic additive that can fuel healthy and resilient gardens and landscapes. Other benefits from composting are many, including helping soil retain moisture, improve drainage, control erosion, remediate toxins, and reduce weeds and disease.

Many towns have large-scale composting operations to turn residents’ yard waste into beneficial compost and keep it out of the waste stream.

The practice and variety of techniques for composting are ancient: records date as far back as 2334 BC in Mesopotamia; bokashi, a method that uses fermented bran, dates back to the 1500s in Japan; and in Germany, hügelkultur, or mound culture, has been used for hundreds of years.

The use of manure to enhance the fertility of soil for crops was common practice as the United States developed. George Washington and Thomas Jefferson employed composting to improve the soil on their farm holdings. But it was the combination of severe drought and unsustainable farming practices on America’s prairies in the 1930s, known as the Dust Bowl, that initiated the government’s creation of the Soil Conservation Service to introduce the widespread use of composting to protect our nation’s diminished soil resources.

The Soil Food Web
Our understanding of the science of composting continues to grow. What made sense and was thought to be a good idea historically has emerged today into a fascinating exploration of soil, its many inhabitants, and the role they both play in healthy ecosystems.

Soil is terrifically diverse, with an estimated 10,000 to 50,000 different taxa in just a teaspoonful of healthy garden soil. All this by way of saying that there are a gazillion invisible organisms below our feet facilitating equally as many exchanges of resources between plants and soil denizens—all this making our food, fodder, forests, and even fresh air, possible. Who knew?

In addition to providing a rich planting medium, compost increases the resilience of our local landscapes by buffering temperature extremes in the soil.

Why Compost?
Roughly one-third of the food that is intended for human consumption in this country ends up in landfills. According to the EPA, food waste is the single most common material landfilled and incinerated in the United States, and the resulting greenhouse gas emissions (just from incineration alone, not including what is lost through landfill emissions) is equal to the “annual carbon dioxide emissions of 42 coal-fired power plants.” That doesn’t factor in the agricultural demands on freshwater for irrigation, fertilizer production and use, and energy consumption related to food processing and transportation.

Food scraps can ultimately generate a composted soil amendment that captures and stores carbon, which means that carbon that would otherwise escape to the atmosphere remains in the soil, where it builds a healthy soil food web. In fact, soil is the earth’s second-biggest storage locker after the ocean.

And healthy soil is resilient: it can better resist and recover from disturbances. By containing a diverse array of organic matter in various stages of decomposition, compost in soil is a buffer to weather extremes such as drought and excessive wet conditions. That means less need for irrigation and a soil texture that mitigates erosion.

In the garden, the superpower of compost is that it provides a slow release of nutrients for soil organisms (yes, all those wee-beasties below our feet) as they breakdown and consume organic matter. This provides a time-honored alternative to synthetic fertilizers—many of which are made from petroleum and require high temperatures (also relying on fossil fuels) to produce. Inorganic fertilizers are salt-based, which provide quick-release nutrition for plants, but are harmful to the diversity of organisms in the soil.

There are many ways to compost, including this galvanized compost can made by Behrens.

How to Compost
Composting doesn’t have to be a heavy lift—although it could be said that the composter will do some heavy lifting, it’s the microbes that do the real work. There are many ways to generate good food for your soil and garden plants—from that way-back pile in your yard, to more sophisticated systems (including, now, electric countertop composters) that provide ample opportunities to begin.

The Key Principles
Providing a ratio of “brown (carbon) to green (nitrogen)” amendments to your compost pile is key. This ratio favors more carbon than nitrogen (in the order of 25 or 30 parts carbon to 1 part nitrogen) to get the correct alchemy for the final product. Too much carbon from woody debris such as leaves and twigs, straw, shredded newspaper, or sawdust (browns) will cool down the process, while the addition of plant materials such as grass clippings, food scraps, and manure from herbivores (greens), heat the pile up (necessary to enhance decomposition and kill weeds and pathogens). Too hot and you will kill off the very organisms that are making the pile into soil; too cold and it will take longer to get your compost, and undesirable organisms and weed seeds will survive.

Lest this sound too complicated, remember that even an infrequently attended compost pile will eventually make organic soil. It all depends on how impatient you are.

The other practices for a good compost pile include introducing air and, if needed, moisture. It’s generally agreed that a compost pile should be a minimum of one cubic yard (3’ by 3’) to get the best surface-to-volume ratio for decomposition.

Manually turning your pile helps mix ingredients while keeping air available for all those decomposing organisms. It’s also possible to use perforated pipes throughout a pile to enhance air movement, or employ an auger to make air passageways into the pile. Added water is only needed if there is extended drought; generally, even when it looks dry at its perimeters, an active pile will retain moisture below the surface.

What we can see in our soil is far less than the full spectrum of life that occupies it. These myriad organisms break down raw organic material and make nutrients available to plants.

Compost Tea
It’s worthwhile to note the usefulness of making and using compost tea, a spin-off from your compost pile that can generate a bonus liquid fertilizer and foliar spray. The process can be as easy as chopping up a variety of greens (including weeds) in a five-gallon pail and adding (chlorine-free) water and letting it sit, covered and out of the sun, for several weeks. What you end up with may not smell sweet, but enthusiasts will tell you that you are adding a lot of varied nutrients and other elements to your soil and plants.

Another inexpensive and faster approach entails collecting a cloth pouch of good compost and submerging it in a five-gallon pail (again adding chlorine-free water) and employing a small aquarium bubbler to keep the water oxygenated. This can provide a finished product in one or two days.

It’s hard to go wrong with composting. The only downside can be attracting wildlife if you haven’t sufficiently buried attractive food scraps, or turned your pile to reduce potential odors. The possibilities are endless for generating a powerful amendment to your gardens and home landscape. And the benefits reach far beyond your gardening aspirations.

Some Great Resources:

• The Regenerative Grower’s Guide to Garden Amendments: Using Locally Sourced Materials to Make Mineral and Biological Extracts and Ferments by Nigel Palmer (Chelsea Green Publishing, 2020). An extraordinary dive into all the possible concoctions that can be made using local ingredients and for little or no cost.
• The Complete Compost Gardening Guide by Barbara Pleasant and Deborah L. Martin. (Storey Publishing, 2008). Recommended by the UConn Master Composter program.
• Teaming with Microbes: The Organic Gardener’s Guide to the Soil Food Web by Jeff Lowenfels and Wayne Lewis (Timber Press, revised edition, 2010). An excellent read about all those soil organisms below our feet.
• The Compost Tea Brewing Manual by Elaine R. Ingham, PhD (Soil Food Web Incorporated, 2003). Ingham is a founding pioneer of the Soil Food Web concept.
• Soil Biology Primer: A free online pamphlet from the Natural Resources Conservation Service, https://www.nrcs.usda.gov/wps/portal/nrcs/main/soils/health/biology/.

Judy Preston is a local ecologist active in the Connecticut River estuary