A few years ago, one of our best loved chickens died. Despite her constant search for a hole in the garden fence, Cacciatore was a wonderful earwig eater and provided our family with beautiful, light brown eggs. Mom liked having her around while she was weeding, so instead of burying her way out in the field somewhere, I decided to compost her.
Composting farm animals like chickens and cows is a feasible and efficient way to return massive amounts of nutrients to the soil. “Offal,” as the carcasses of animals are called, is an invaluable resource for composting. Temperature requirements for this kind of compost are higher and need to be sustained for a longer period of time, which means a lower carbon to nitrogen ratio. The more nitrogen in the pile, the hotter the pile will be. Sustaining this heat is the trick. There needs to be plenty of water and oxygen in order to provide the heat loving bacteria with enough energy and food to keep up the good work.
When I decided to compost Cacciatore, this is what I did. I gathered all the nitrogen I could find—green grass clippings, kitchen scraps, and chicken manure—and mixed these with bulky carbon material for aeration. I watered as I worked until the finished pile, about four cubic feet inside strawbale walls, was as wet as a wrung out sponge. A thick layer of straw served as insulation and discouraged flies.
After two days, the dial on my compost thermometer registered 160 degrees Fahrenheit. I dug into the center, put Cacciatore in, covered her, and waited. The pile stayed at 150 for about a week. I turned it once more in the fall, watering as I worked, and the temperatures rose again to 160 for another week. Turning the pile twice allowed any material on the edges to have its turn in the hot center. This ensures that any harmful bacteria or weed seeds all got hot enough to be completely broken down and inert.
I let it sit for a few months until the time came in late summer to move the compost pile into the garden. With every shovelful, I half expected to see bone, beak, or feather, but crumbly, deep dark humus was all I found. Cacciatore was finally welcome inside the garden fence.
How does such a complete transformation happen inside such a simple pile of kitchen waste, garden trimmings, and manure? With the help of billions of microorganisms. Where on earth will you find these microorganisms to help you transform waste into compost? Don’t worry, they have already found you. Just building a compost pile is like lighting a neon sign that buzzes, “Microorganisms Welcome!”
When Carbon and Nitrogen are combined in the right ratio (25 or 30 parts carbon to 1 part nitrogen), when there is enough moisture, some oxygen, and enough mass, the bacteria already found on the waste begin to go to work.
When temperatures are high in a compost pile, anywhere from 130-160, heat loving bacteria (thermophyllic) are hard at work in compost. On a chilly day you can see the evidence as steam rising from your pile. Bacteria sweat. Like us, they burn carbon and release carbon dioxide and water into the air. They can sustain this work for 3 days to a week, just the right amount of time for many of the pathogens and weed seeds in the middle of the pile to break down (tomato and squash seeds are another story).
Turning the outside of the pile to the inside will ensure that the rest of the pile gets a seat in the middle, too. You can turn a pile by hand. If you are lucky enough to have a front loader handy, this is a fast way to turn a large pile on a farm. Composting in a barrel allows for easy turning either raised on an axel so you can turn it with a handle or just on the ground so you can roll it. Worms will turn the compost for you (see “worm husbandry”).
When temperatures fall between 80 and 100 degrees, conditions are right for mesophyllic (middle loving) bacteria to explode in numbers. Now the pile smells “earthy,” like soil. This is the pleasant halitosis of the bacteria actinomycetes (act-tee-no-my-see-tees). They are breaking down the compost into even tinier particles, and you can see them as white, webby strands throughout the compost pile.
Fungi make their appearance at the very end. The fruits of their labor bloom as mushrooms on the surface of compost, telling you it will be ready soon. You will know compost is ready when it smells good, like rich soil, is dark brown, and looks nothing like the slimy, rotten waste it was before. According to a 1996 article in the New York Times by Nicholas Wade, bacteria “comprise as much as half of all living things on the planet.” Bacteria are found on almost every surface of the earth, whether internal or external. Lucky for us, they work to our benefit in compost piles, our stomachs, landfills, wine casks, breweries, forest floors, and sourdough bakeries. Such a transformation is miraculous, and the end result, humus, is still a mystery to scientists, but there are some things we do know.
We know that humus is the most stable form of plant food available on the earth and can remain in the soil, providing plants with nitrogen, for over 100 years. We know that over half of the humus on the planet has been lost to over grazing and over working the land. We know that humus takes a long time to form. The longer a compost pile cures, the more stable humus you will find. Like good bread, wine, and beer, it’s worth the wait. One to two years is a safe bet. Then it’s time for the compost to return to the garden, the fruit trees, the house plants, and the earth.