Many experts insist that in order to make good compost, it must be turned regularly, but is that really the case?
Consider: When leaves fall each autumn and dead trees topple over in hardwood forests, is that decaying matter turned over? No, it just sits there turning into rich leaf mold. A common myth is that you cannot make good compost without regularly turning the compost pile. It’s not true. You can make your life easier by eliminating the compost-turning step.
Compost-turning proponents tell us that turning the compost pile does four things:
- It supplies oxygen to aerobic microbes.
- It eventually places all parts of the pile into the high-heat area.
- It mixes all compost ingredients for a better-looking end result.
- It speeds up composting.
Toss Out Numbers 3 and 4
But if you’re the only one using your own compost, then worrying about how it looks once the compost is buried in your garden is ridiculous. It’s in the ground, so who cares how it looks? Gardening, by its very nature, is not a hectic and fast-paced activity. Why speed up composting if it’s not needed? That eliminates reasons three and four.
Importance of Oxygen
The first point on the list — adding oxygen to compost to benefit aerobic microbes — is an excellent argument. Without adequate oxygen, anaerobic decomposition develops, creating a stinky mess. Commercial compost businesses pump air into compost piles, with big fans blowing through holes in aeration tubes.
How do you aerate garden soil? You do it by adding humus, or the compost that you’re making. Well, that same principle can be applied to compost production. You can add minute air spaces to the compost pile by layering in coarse items, such as weed stalks, straw, hay, and even egg shells.
The king of organic gardening knowledge, the late J.I. Rodale, wrote in his 1960 book, The Complete Book of Composting, “Good compost can be made without turning by hand if the materials are carefully layered in the heap, which is well-ventilated and has the right moisture content.” Ventilation, layering and moisture are keys words in Mr. Rodale’s statement. Coarse material layered between moist animal manure gives you excellent compost ingredients.
Heat Layer of a Compost Pile
To analyze the second reason for turning a compost pile — that it places all parts of the pile into a high-heat environment — you first need to understand the mechanics of compost heat. It’s a result of a blend of carbon to nitrogen, with various bacteria breaking down this combination. The perfect carbon/nitrogen blend is 20 parts carbon to one part nitrogen. Carbon comes from plant matter. The best nitrogen sources originate from animal manure.
Three bacteria types break down the compost. Bacteria that enjoy cool temperatures of 59 degrees Fahrenheit (15 degrees Celsius) and lower are psychrophilic. They work very slowly. Mesophilic bacteria like medium temperatures of 68-113 degrees Fahrenheit (20-45 degrees Celsius). Thermophilic bacteria love temperatures above 113 degrees Fahrenheit (45 degrees Celsius). All of these bacteria work together by combining carbon and nitrogen to create carbon dioxide and energy. Part of the energy helps reproduce more bacteria. The remaining energy creates heat.
Just after you apply layers of carbon (plant matter) and nitrogen (manure) to compost, the mesophilic bacteria multiply, boosting the temperature of that layer to 111 degrees Fahrenheit (44 degrees Celsius). Add additional layers and your first layers go into a second stage where thermophilic bacteria thrive, boosting the temperature to roughly 158 degrees Fahrenheit (70 degrees Celsius). This thermophilic activity is located just a couple of layers under the compost pile’s top surface. As layers are added, the original layer cools, bacteria die off, and fungi takes over decomposition.
Mixing Cools the Hot Bacteria
Stir up these layers by turning over your compost pile, and you cool down temperatures below the level enjoyed by thermophilic bacteria, or those that perform the most robust breakdown of the carbon and nitrogen in your compost. So, continuously stirring your compost actually cools that heat layer just under the top of the pile, instead of putting all areas of the compost into the heat, as suggested by compost-turning proponents in their second argument.
A better composting method is to lay down layers of course plant matter with layers of manure. High-moisture manure is best: pig manure, at 82 percent moisture; cattle manure, at 80 percent; and horse manure, at 75 percent, are best. When using sheep manure, at 68 percent, or chicken manure, at 56 percent, you need to add a daily bucket of water to your compost.
Continue layering like this for a year. Start a new compost pile of layers on year two and allow the year one compost pile to rest during the final fungal breakdown. At the end of the second year, add your compost to the garden and enjoy tremendous gardening results without the backbreaking chore of always turning the compost pile.
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