Seaweed and Kelp: If you live near the sea, don't scorn the sea's free gift of kelp and seaweed. These are high in potash as well as many minor elements. Additional nitrogen helps speed breakdown.
Nut Shells: Pecan shells, peanut husks, cocoanut fiber and other nut wastes make excellent compost. One precaution: avoid shells of
walnuts. They contain a chemical that inhibits plant growth and works like an antiseptic to kill off bacteria.
Tobacco Stems and Wastes: An excellent source of humus and a good soil conditioner when composted.
Fish Wastes: When cleaning fish, always save the offal for the compost pile. Salt-water fish in particular contribute all the minor elements as well as the three major elements in their skin, bones and offal.
Wool Clippings: Worn-out wool clothing should be buried in the compost pile. It will take about two years to decompose. Dark colors rot more slowly than light tones.
Corn Cobs: Although rather high in silica, corn cobs do contain considerable potash and thus are useful in the compost heap. Both nitrogen and phosphorus (at least a sprinkling of the latter) will improve the compost produced by corn cobs.
Sewerage Sludge: If it can be had for the hauling, air-dried sewerage sludge is worth composting. However, be sure it goes through at least a full year's decay before it is used. Amoeba can survive in sewerage sludge and cause infection in human beings. A full year's composting, if the pile is turned, should eliminate them.
Lawn Clippings: They should be added to the compost heap rather than allowed to lie on the surface of the lawn, where they build up a duff that fosters fungus diseases. Allow the fungi in the compost pile to work on them instead.
Straw, Hay, Cattails: These are low in nitrogen. A compost "food" is needed to rot them. The finished product closely resembles barnyard manure.
Weeds and Discarded Plants from the Garden: Use these only if not visibly infected with plant diseases. If weeds have formed seed, be sure to place them deep in the pile so the heat of composting will kill the seed.
Tanbark: Not easy to find nowadays, but if available it can be composted with the "food" mixture recommended for straw.
Cotton Nolls and Wastes: Difficult to start a compost with this type of material, but it yields a high percentage of humus. Allow about a year for breakdown.
Paper Scraps: Mentioned here only because paper is often a subject of doubt. Almost pure cellulose, it requires both nitrogen and starches or sugar in order to break down. A small percentage of paper in the compost pile won't hurt. Actually, practically anything of organic origin can be composted in time. I once made some excellent compost with a mixture of straw and some spoiled latex paint, combined with waste blood-albumin glue!