There are so many uses for compost that it’s tempting to try all of them. If you can produce only a limited supply in your backyard, however, you won’t have enough to go around. Fortunately, compost is available through sources other than your own compost pile, so you can stretch your supply. The following are a few types of compost found in many regions; other equally effective materials may be available in your area.
Since so many states have passed legislation excluding yard waste from landfills, communities across the United States are setting up their own composting operations. Leaves, grass clippings, brush, and other organic materials are still collected by the trash pickup system, but they end up at a composting site instead of a landfill. In most cases, the materials are laid out in huge windrows hundreds of yards long. Large machines designed to turn compost move down the windrows every few days, turning the piles.
The municipality uses the compost in public areas, such as parks, athletic fields, and landscaped areas around public buildings. A large percentage is sold to the nursery industry, usually at a reasonable cost. Often, there’s still compost left over for use by residents. In some communities, the compost is offered free to locals who are willing to pick it up. In others, you can buy it at your local garden center.
Composted Sewage Sludge
Sewage, the liquid effluent from industry and the toilets of private residences, presents as serious a disposal problem as trash. Again, composting promises to diminish the problem. Hundreds of cities have already undertaken programs to compost sludge, the solid residue from sewage waste. The finished product is a dark, humus-rich material suitable for use in residential landscapes. In the coming years many more cities are expected to institute similar programs.
The composting procedure varies somewhat from city to city, but the basic approach is similar. After the sludge emerges from the sewage treatment plant, it’s mixed with wood chips and composted at high temperatures to kill disease organisms. When the composted mixture is dried and cured, the large wood chips are screened out. Since composted sewage sludge tends to have a higher organic content than homemade compost made from yard waste, its benefits usually last longer in the soil.
For many years, composted sludge wasn’t considered safe for use in home applications because of concern about heavy metals that might prove toxic in home landscapes. The heavy-metal content of the sludge was primarily a problem in industrial areas, and regulations limiting metal pollutants entering the sewage system have reduced that problem.
People may wish to avoid using composted sewage sludge on vegetable gardens just to be absolutely sure, but in most cities the heavy-metal content of the finished product is well below safe tolerances for all home applications. Composted sewage sludge may be available directly from a municipality or from the utility responsible for sewage treatment, or it may be sold through garden centers or soil yards.
Home gardeners in some regions have access to another excellent source of humus—the medium in which mushrooms are grown, or mushroom compost. Mushrooms are grown in a mixture of straw and manure, which is no longer suitable as a mushroom-growing medium after the mixture decomposes. The spent bedding, which is either sold directly by mushroom farmers or is marketed through garden centers or soil yards, makes an excellent soil conditioner. To be sure that the manure won’t burn plants, let the mushroom compost age for at least six weeks before using it in your garden.
Mushroom compost put through a shredder with homemade compost makes a wonderfully soft, uniform material that can be used anywhere in the home landscape.