Everything in Its Place
Put the compost in a pile;
The beans and corn in rows,
The tools, we know, go in the shed
And by the road, a rose.
Visiting gardens is my stock in trade, and many gardeners who have shown me their beautifully manicured, artfully planted gardens, finally exclaim at the end of my visit, “Now let me show you the best bit!” And with that we scuttle over to . . . the compost heap. “Isn’t it wonderful?” they ask in all dewy-eyed earnestness. And I have to agree. A compost heap is, indeed, a thing of great and unrivaled beauty. And to achieve it is as easy as 1–2–3.
Compost is nothing more than decomposed organic matter. Yet this simple substance is a gardener’s most valuable ally, which earned it the nickname of “gardener’s gold.” There is certainly no better gift that can be given to a garden, and that is really the only reason a gardener needs to become a composter.
There’s no mystery to making compost, and gardeners can easily make it for free using materials already on hand. Nearly every compost pile starts with everyday kitchen wastes—from potato peelings to coffee grounds. Kitchen scraps are only the beginning, though, since garden wastes like weeds, leaves, and spent plants also belong in the mix. In short, a compost pile starts with materials that typically would be tossed into the trash and eventually make their way to a garbage dump. Gather these same materials for composting, though, and all it takes is a few easy steps to help them break down into rich, crumbly compost. No rocket science or bioengineering skills are needed—just organic garbage, a little time spent mixing materials, and patience.
A compost pile may look lifeless, but there’s a surprising amount of natural activity going on inside it. Countless bacteria, fungi, and other organisms feed, grow, reproduce, and die as they break down kitchen and garden waste and recycle it to make compost. This process of decomposition occurs gradually in nature, and a compost pile simply takes advantage of nature’s processes, helping them to go a little faster. The end product—compost—is an invaluable soil amendment for any garden or plant container. Also, composting recycles materials that would otherwise be treated as waste and end up in landfills, taking up large amounts of space, blighting the landscape, and potentially causing other environmental problems. Understanding the decomposition process—which is basic science, really—will help every gardener to become a successful composter. So put aside any fears of science and read on.
After kitchen scraps and yard wastes have been collected and mixed in a pile, the composting process begins. Soil microorganisms—the “life” of the soil—including tiny living creatures, such as helpful bacteria (including actinomycetes), protozoa (single-celled animals), and fungi, release enzymes to digest and thereby decompose the compost materials. At the same time, the chemical processes of oxidation, reduction, and hydrolysis also release the nutrients and energy the microorganisms need to live, grow, and reproduce. Oxidation is the primary way that energy is released and made available to microorganisms, and carbon is the most important source of fuel for the oxidation process. As the carbon in the compost materials burns or oxidizes, the compost pile heats up.
The easiest-to-break-down materials in the compost pile are digested first, and the excess heat that builds up kills off any harmful bacteria that may be present. Eventually, the initial composting activity slows down and the compost begins to cool. The partially decomposed products that are still left become food for an even wider array of microorganisms, plus the slightly larger creatures—such as mites, millipedes, centipedes, sow bugs, and other insects—that help to chew up larger particles and mix up the remaining compost materials. This expanding population of creatures and fungi breaks down everything still further: Carbohydrates (starches and sugars) break down into simple sugars, organic acids, and carbon dioxide; proteins break down into peptides and amino acids; and large bits of material break down into many smaller ones, exposing more food for the microorganisms to digest.
In this final stage, the microorganisms (mostly actinomycetes and fungi) break the peptides and amino acids down into nitrates—a form of nitrogen that plants can use—and atmospheric nitrogen. The larger organisms continue to chew and churn the organic matter until only fine black particles remain as the finished compost.
“Finished” compost (as a well-rotted pile is called) is a mound of dark, moist organic matter that contains a light dose of nutrients and a vibrantly healthy herd of beneficial microorganisms. Both the organic matter and the microorganisms will keep on working hard after the compost is dug into the soil at planting time, spread onto garden beds as mulch, or incorporated in potting mix to grow plants in containers.
While the essentials of making compost at home are simple, the ways it can be made and used can be quite varied. All organic gardeners agree that compost is the foundation of any great organic garden and that being a compostologist is hugely rewarding!