There are a variety of composting methods. The method you choose depends on the material you’re composting and how much effort you want to put into it.
Regardless of the method you choose it is important to remember that compost has four main ingredients: Browns, Greens, Air, and Water. Browns are dry, woody materials such as fallen leaves, pruned shrubbery, pine needles, newspaper, and so on. Greens are moist, nitrogen-rich materials such as fruit and vegetable trimmings, grass clippings, and fresh weeds. Air and water are the essential ingredients without which our industrious microfauna could not transform Browns and Greens into compost.
Below is a brief description of the most common methods of composting. (See also, "Discount Bin Descriptions")
Take note: Whenever you compost fruit and vegetable trimmings, the County Environmental Health Department requires a rodent-resistant system. Use a container with a lid, a floor, and no opening greater than 1/4-inch, or bury food scraps at least one foot under the soil surface.
Plant Trimmings Only
The simplest way to compost is by collecting your yard trimmings and making a pile of them. The pile can be an open one, or you can keep it in a bin.
No Fuss Compost or “Cold Compost”. Add chopped or unchopped yard trimmings to a rodent-resistant bin on an ongoing basis. Maintain the pile by keeping it as moist as a wrung-out sponge. Harvest finished compost from the bottom and center of the pile after 12 to 18 months.
Active Compost or “Hot Compost”. Chop yard trimmings into pieces 6 inches or smaller and mix them into an open pile or simple bin. Be sure to balance Browns with Greens. Add new materials as often as you like. Maintain the pile by turning or mixing it about once a week and keeping it as moist as a wrung-out sponge (if it’s an open pile, covering it with a plastic tarp will help retain moisture). Harvest finished compost by sifting out coarse, unfinished materials after 3 to 8 months.
Fruit, Vegetable, and Plant Trimmings Combined
When adding fruit and vegetable trimmings to a pile, one must take into account that these high-moisture, high-nitrogen materials break down quickly and can be a bit soppy. A good rule of thumb is to never let fruit and vegetable trimmings make up more than a third of the compost pile. Fresh food trimmings can also attract animals, so use a rodent-resistant bin, mix them with plenty of Browns, and bury them deep. Never dump food and run!
Mixed Compost. Chop yard trimmings into pieces 6 inches or smaller and put them in a rodent-resistant bin. Bury food scraps in the center of the pile, mixing well as you add them. Add material as often as you like, keeping a balance of Browns and Greens. Maintain the pile by turning or mixing it about once a week and keeping it as moist as a wrung-out sponge. Harvest finished compost by sifting out coarse, unfinished materials after 3 to 8 months.
Fruit and Vegetable Trimmings Alone
There are several systems for composting fruit and vegetable trimmings alone. All of them are designed to take advantage of the high nutrient content and quick breakdown of these materials.
Worm Composting. This method of composting began to be popularized in the United States about 20 years ago when Mary Appelhof published Worms Eat My Garbage. Appelhof found that red wiggler earthworms don’t mind living in a box, and will gladly eat the same things we do. A pound of red worms can eat 65 pounds of food trimmings in less than three months. The worm castings, or vermicompost, are a high-quality soil amendment that can be used for house and garden plants.
Underground Composting. Dig an 18-inch hole in any empty part of the garden. Chop and mix food scraps into the soil. Cover with at least 12 inches of soil. No harvesting is necessary with this system—the compost enriches the soil directly. One to three months later, you can bury more compostables in the same place.
Closed-Air Systems or Food Digesters. Rather than bury food scraps, you can put them in a container that holds 6 to 10 months’ worth. Closed-air bins have tight-fitting lids and holes or a wire screen on the bottom to provide contact with the soil and prevent rodent entry. They can be made from garbage cans or bought from a garden supply catalog. Your best bet is to buy or make two, so you can add new materials to one while compost is maturing in the other.
Select a convenient, well-drained location in the garden, dig a hole, and bury the bottom 12 to 18 inches of the bin. Pack the soil firmly around the bin to make sure it is secure. Add food trimmings to the bin on an ongoing basis, and cover each addition with a layer of shredded newspaper, dry soil, or sawdust (this will keep odors down and discourage fruit flies). Keep the lid on tight. When the first bin is three-quarters full, dig a hole for the second one and begin to fill it. When it is three-quarters full, the first bin should be ready for use in the garden. Empty it and begin the process again.
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