They have some value in speeding up decomposition during cool spring or fall weather. Just as effective, however, if available, are bacteria-filled screenings from an old compost pile, well-rotted manure or soil from a rich field. If the only soil available for building a compost pile is a sandy loam, a commercial compost culture will speed breakdown. These should be cultures of bacteria such as Activo, not the herbal mixtures frequently mentioned in organic gardening publications.
There is no reason why the pile should have an offensive smell if properly covered with soil: a 4-inch layer of earth absorbs all odors. However, if blood, manures and other rich organic substances become a bit odoriferous, add a little extra superphosphate. One caution should be given: do not add large amounts of fresh wood ashes
to a compost pile as they form lye and can injure bacteria. Mix fresh ashes with a little damp soil and allow them to stand for a day or two, after which they can be used safely.
ORGANIC MATERIALS WHICH CAN BE COMPOSTED
Dried Leaves: This is the most common material available to home gardeners. It is valuable as a source of humus, but don't take seriously the "richness" of this material often mentioned by uninformed individuals. Before trees and shrubs drop their leaves in autumn, they withdraw starches, sugars and other food elements from the leaves. Leaves are largely cellulose, so additional starches as well as nitrogen are needed to rot them. Leaves are best if mixed in the compost heap with such materials as stale bread, spoiled flour or meal, and so on.
Table Wastes: Richness of this source depends on how extravagant you are. The higher the percentage of meat scraps in table waste, the more valuable it is in compost.
Sawdust: If the master of the house has a home workshop, or if sawdust and shavings are available from a local source, wood wastes make excellent compost. If wanted as a source of humus, use plenty of nitrogen with these wastes, but if you want compost that is less completely converted to humus, add more starchy material and less nitrogen to the pile.
Chicken Manure and Poultry Wastes: Local broiler plants often throw away offal, feathers, etc. Many poultry raisers find chicken manure a nuisance and are glad to give it away; it is sufficiently high in nitrogen but not in phosphorus and potash. These two elements plus starch should be added to speed up chicken waste breakdown.
Brewery Wastes: The spent hops from breweries are about on a par with leaves and require about the same composting attention. One difference: hops are usually wet when received.