Standard Backyard Composting- composting without earthworms. Part 1

This chapter heading is somewhat of a misnomer, since the average compost pile, like it or not, contains earthworms; thus, those who are composting their organic waste in a standard compost pile are actually relying on composting earthworms as well as thermophilic bacteria, which thrive at very high temperatures, to turn their organic waste into a combination of humus (compost) and earthworm castings. For the most part, the thermophilic bacteria reside in pile's hot interior while the earthworms do their thing at the bottom and sides of the compost pile, where it is much cooler. There certainly is nothing wrong with this hybrid composting technique. In fact, as will be discussed in some detail in part 11, I pre-compost most of the oak leaves and horse manure fed to my earthworms at the Mount Diablo Worm Farm before applying it to their bedding in the windrows. Having said this, I would argue that, for a home owner who simply wants to compost his kitchen waste, news papers and maybe a few grass clippings, composting primarily with earthworms is a more effective way to achieve this goal. This is so, because it takes a lot less time, as well as physical labor, to compost if you let the earthworms do most of the work for you. Earthworms also create a much more valuable nutrient rich organic fertilizer than the humus like soil conditioner produced in a standard compost pile, even if it happens to have a few earthworms in it. The importance of size. Compost bins come in many sizes and shapes including the rotating plastic drums that are sold at garden supply stores. These rotating devices are attractive because you simply rotate them to aerate the organic material within their tumblers. However, to work efficiently a compost bin, or pile, must be large enough to contain at least one cubic yard ( a pile 3' X 3' X 3' in size) of organic material. Most of the rotating drum composters are much too small to achieve this goal. Size is important because smaller compost piles are incapable of supporting enough thermophilic bacteria to achieve efficient, rapid, decomposition. Having said this, organic material will rot in smaller compost piles, it will just take a lot longer for it to happen. It also is worth noting that a compost pile must maintain a minimal temperature of 131°F, for three consecutive days, to kill weed seeds and plant pathogens that inadvertently may have been placed in the pile. Although larger piles which generate a lot of internal heat, are more efficient than smaller piles, there are practical considerations which serve to limit the size of a compost pile. In this respect, compost piles larger than 5' X 5' X 5' must be turned more frequently to prevent them from becoming anaerobic because air will not naturally penetrate more than 18'' to 24"s into a compost pile. It also is more difficult to turn the material in the pile if it is excessively large. Since aerobic decomposition requires oxygen, compost containers should have holes or slats in their sides to encourage the flow of air throughout the pile. Plastic barrel containers make good composters if large holes drilled in their sides, at least one for every square foot of surface area. Since it is difficult to turn the material in a solid walled container (to aerate it) many gardeners use a flexible walled containers formed from a wire mesh, like chicken wire, to contain the material they wish to compost. I use 10 foot sections of four foot wide vinyl coated welded wire made by Yard Gard™ to make my composting cages. This wire has a 2'' X 3'' mesh which is easier to handle than chicken wire. Square wire cages may have posts in their sides but it is simpler to use a circular self standing wire container than it is one with posts. Next week, in part 11, I will discuss what can be placed in a compost pile; how to maintain the pile; how to tell when the compost is finished; and, how to use the compost. In the meantime, if you have any questions, please contact me at docmerrill@aol.com.