Organic Gardener's Composting by Steve Solomon

Making Humus

Before we ask how to compost, since nature is maximally efficient perhaps it would benefit us to first examine how nature goes about returning organic matter to the soil from whence it came. If we do nearly as well, we can be proud.

Where nature is allowed to operate without human intervention, each place develops a stable level of biomass that is inevitably the highest amount of organic life that site could support. Whether deciduous forest, coniferous forest, prairie, even desert, nature makes the most of the available resources and raises the living drama to its most intense and complex peak possible. There will be as many mammals as there can be, as many insects, as many worms, as many plants growing as large as they can get, as much organic matter in all stages of decomposition and the maximum amount of relatively stable humus in the soil. All these forms of living and decomposing organisms are linked in one complex system; each part so closely connected to all the others that should one be lessened or increased, all the others change as well.

The efficient decomposition of leaves on a forest floor is a fine example of what we might hope to achieve in a compost pile. Under the shade of the trees and mulched thickly by leaves, the forest floor usually stays moist. Although the leaves tend to mat where they contact the soil, the wet, somewhat compacted layer is thin enough to permit air to be in contact with all of the materials and to enter the soil.

Living in this very top layer of fluffy, crumbly, moist soil mixed with leaf material and humus, are the animals that begin the process of humification. Many of these primary decomposers are larger, insect-like animals commonly known to gardeners, including the wood lice that we call pill bugs because they roll up defensively into hard armadillo-like shells, and the highly intrusive earwigs my daughter calls pinch bugs. There are also numerous types of insect larvae busily at work.