This approach involves the least amount of time and energy on your part. It requires low maintenance or even no maintenance. You just throw organic materials into a pile and let them rot unattended. There’s no need to worry about the technical aspects of composting, such as the carbon-nitrogen ratio.
A passive compost pile takes longer to produce finished compost than an actively managed one. People who choose passive composting aren’t usually in a hurry, however. Except in the eyes of true composting devotees, there’s little practical difference between compost produced the passive way and compost produced by a more managed approach. In both cases, the finished compost is an excellent soil-building material.
Passive compost piles are one of two types: freestanding or contained. The only reason to put a passive compost pile into a bin or enclosure is to make it neater. The passive pile can easily handle all organic waste except meat and animal products, and it yields a modest bonus in the form of soil amendment once or twice a year. That’s not a bad return for a minimal amount of time and energy.
Creating the Simplest Passive Pile
Collecting organic materials in a freestanding pile is the simplest way to make compost. Although such collections are seldom referred to as compost piles, they exist behind many houses. Homeowners with a little extra land frequently have a pile of organic material slowly decomposing “out back.” The collection site is usually the spot where you put organic trash—leaves, grass clippings, brush, and weeds—when there’s too much for the regular trash pickup or when there isn’t any collection service for that type of material.
With these simple piles no one worries much about insect or animal pests. If the pile smells occasionally, it’s usually far enough away from the house so that the odor doesn’t bother anyone. These piles are treated as trash heaps; they’re seldom mined for the valuable humus that rests at the bottom. It just sits there, enriching the weeds around the heap.
If these organic trash heaps were organized just a little bit, they would be less unsightly and would produce excellent compost. A three-sided enclosure, usually made of chicken wire or concrete blocks, is helpful in keeping the pile neater.
With piles of this sort, technical issues such as the carbon-nitrogen ratio of the materials aren’t really a consideration. As waste accumulates, it’s simply added to the pile. Perhaps the most important decision is how to handle woody materials. Unless you cut them up, the pile tends to become more of a brush pile than a compost pile. A woody pile decomposes extremely slowly, usually over many years, and becomes enormous quickly.
Cutting up the brush with pruners, a machete or—even better—a chipper-shredder keeps the pile compact and allows most of the organic waste to decompose in less than two years. Don’t throw kitchen waste on a simple compost pile. Food scraps attract pests, such as flies, dogs, opossums, raccoons, rats, and skunks. Large amounts of grass clippings or freshly pulled weeds thrown onto a simple pile may smell for a few days, but the odor dissipates fairly quickly.
People who build this type of pile don’t usually cover it because they’re not worried about rain slowing down the rate of decomposition or leaching nutrients from the finished product. The pile serves more as a yard waste depository than a compost production site.
After a couple of years, a simple compost pile always has some aged compost on the bottom. This material is covered by layers of organic material in less advanced stages of decomposition. After the first few years, most simple piles produce a few cubic feet of finished compost yearly. Remove the finished compost whenever you need it, and keep adding new material to the pile.