The Science of Composting
Composting is one of the easiest ways to work toward a bit more sustainability in your lifestyle. If you grow anything—be it vegetables, flowers, or even your lawn—composting is an essential way of transferring the nutrients from your yard and kitchen waste into nutrition for your plants.
Compost is broken down in three general ways: through bacterial decomposition, fungal decomposition, or vermiculture. Your basic backyard compost pile most likely consists of a trifecta of all three methods, but it is important to understand what’s happening in each.
Bacterial decomposition is the most common form of compost creation. Naturally-occurring bacteria chemically break down your kitchen and yard waste into nutrient-dense soil, ready to feed your plants. Bacterial decomposition is one of the faster methods of composting, usually taking only about a year to yield usable soil. A major drawback to this process is the potential smell, as certain bacteria create offensive odors during decomposition. Those bacteria, luckily, are fairly easy to combat. The offending bacteria are almost always anaerobic bacteria—bacteria whose respiration (food to energy conversion) does not require oxygen. Aerobic bacteria which use oxygen during respiration. The simple solution to a smelly compost pile is aeration. Turn your compost over with a pitchfork frequently. In addition to aeration, balancing green waste and waste that has turned brown is helpful. For instance, with every bag of kitchen scraps you put into your compost pile, add an equal amount of wheat straw, dry leaves or small branches.
Fungal decomposition occurs when fungal mycelium penetrates compost and break it down into nutrient-rich soil. Fungal decomposition takes much longer than bacterial decomposition, but is free from any odors and has a far wider range. Research into fungal composting has been on the rise as of late; fungus is now being used to compost plastics and styrofoam. One mycologist has even used oyster mushrooms to compost used cigarette butts! For the home composter, fungal composting is especially useful for those who compost large amounts of woody materials and aren’t in a hurry for usable soil.
Vermiculture uses worms to rapidly break down organic materials into nutrient-rich soil. If you have never heard of a worm bin, it’s worth a quick YouTube search to see one in action. I first encountered vermiculture while working in my high school greenhouse. My teacher excitedly called the three of us in his greenhouse independent study class over to look at his new purchase. What he had was essentially a Rubbermaid box full of newspapers and worms. We weren’t impressed at first, but his excitement was contagious. We dutifully tossed all organic materials into the glorified Tupperware container for weeks, even going so far as to bring our plant-based lunch scraps back to the greenhouse for the worms. It was less than a month before we found the worm bin completely filled with rich black dirt, it was pretty exciting for a group of plant nerds. Worm bins have developed quite a bit from that rudimentary box; they now contain multiple layers, worm ladders, even spouts that dispense “worm tea”—a concentrated dose of nutrients in liquid form.
Vermiculture is a great idea for people in apartments or those who can’t spend time aerating a backyard compost pile. Worm bins can be used indoors and, if used properly, shouldn’t have any unpleasant odors. Red Wigglers (Eisenia foetida) are specialty worms used in vermicomposting. These worms are great compost worms for northern climates because they eat almost all organic matter, but do not survive cold winters. Red Wigglers are not invasive in the Great Lakes region. It is important to buy your worms from a reputable source such as Uncle Jim’s Worm Farm, to avoid introducing invasive worm species into the wild.
Hopefully, this has helped shed some light on that dark and mysterious compost pile lurking at the corner of your yard. I encourage you to experiment with composting, dig a little bit deeper into a method that might interest you by checking online or at your library for more composting resources. Call The Plant Professionals with compost questions. We make our own compost, and are happy to share.