| Commercially available prefabricated
compost bins require little or no site preparation and can be placed
at a convenient outdoor location with easy access and low visibility.
Different composting techniques may be used with different prefabricated
units.
Wire, wood slats, discarded pallets, and blocks or bricks can be
used. It is important to choose materials or designs that provide
air circulation to the compost. The Master Composter Program (listed
in Resources Section) offers technical assistance and plans.
The footprint of a site built compost system should be 4 to 5 feet
square. The pile will attain about 4 feet in height and will need
to have sides to approximately the same height.
Building a Composting Site
Select a level area near a water source that receives an equal amount
of sun and shade.
Remove the sod or grass to expose the dirt in the spot where the
compost will be placed. Transplant or set aside that grass for later
use.
Use 3 to 6 inches of coarse materials such as branches, leaves
or straw as the bottom layer. These are high carbon materials that
provide for air circulation from the bottom of the pile.
The next layer should include high nitrogen materials such as grass
clippings or manure. This is added to a depth of 6 inches.
Repeat the sequence of alternating carbon materials ("browns")
and nitrogen materials ("greens").
The pile is turned every couple of weeks and kept damp, not soggy.
Less turning of the pile slows the decomposition time. A little
soil can be added to "inoculate" the mix with healthy
microorganisms.
Characteristics
The pile will settle and approach 160 degrees F. in the center while
decomposing.
Adding lime, wood ashes, or crushed eggshells will neutralize acids
that may cause odors.
Mix grass clippings and leaves with other materials. Leaves and
grass clippings tend to mat and inhibit air needed for decomposition.
Keep the pile covered with a top layer of grass clippings or leaves.
This will help prevent insect problems.
To avoid the labor of turning, organic materials can simply be
piled up and left. Decomposition will still occur although at a
slower rate.
Vermiculture
Worm castings are considered very high quality fertilizer. Worms
consume food scraps and paper faster than bacteria.
Mix food wastes with dampened, shredded newspaper or cardboard
scraps in covered containers in which air holes have been punched.
Kits can be purchased or instructions are available to do it yourself
(see Resources). Bins are available for large food producers such
as lunch or break rooms.
Suitable compostable materials:
- unprocessed or uncooked kitchen scraps (usually trimmings from
vegetable preparation, used coffee grinds, etc.)
- leaves (rich in trace minerals)
- alfalfa and clover (rich in nitrogen)
- sawdust (good soil builder but slows decomposition)
- garden residue
- weeds (used "green," some seeds may survive)
- grass clippings (will mat without mixing in other materials)
- hair (very high in nitrogen)
Other suitable materials include nutshells, feathers, floor sweepings,
pine needles, tobacco without filters, wood ashes, cotton, wool,
pure silk, natural material clothing, rugs, and wood scraps.
Do not use meat, dairy products, grease, bones, fatty foods or
pet litter.
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