Compost System

DEFINITION

CONSIDERATIONS

COMMERCIAL STATUS

IMPLEMENTATION ISSUES

GUIDELINES

1. Commercially available prefabricated compost bins
2. Site-built compost area
3. Vermiculture
4. Suitable materials

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DEFINITION:

Compost is created by the decomposition of organic matter such as yard waste. Compost systems confine compost so that it can receive air and create suitable temperatures for proper decomposition into fertilizer.

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CONSIDERATIONS:

Landscape waste amounts to about 129,000 tons per year in Austin. This volume of material if composted could create 77,000 tons of fertilizer. Composting results in: (a) saving landfill space, (b) saving energy for transporting the material, and (c) the creation of a high quality fertilizer at the location where it can be used (thereby again saving energy). In addition, plastic garbage bags are saved.

Animal-based food products should not used to create compost. The compost system should function without odors or difficult labor. Prefabricated composting bin systems are available commercially and can function well with minimal maintenance.

Vermiculture, or composting using worms, can be accomplished as an alternative approach to traditional composting methods. Guidance is available from trained persons in Austin.

	Commercial Status				Implementation Issues
	T E C H N O L O G Y	S U P P L I E R S	C O S T		F I N A N C I N G	A C C E P T A N C E	R E G U L A T O R Y
Compost System

	Satisfactory
	Satisfactory in most conditions
	Satisfactory in Limited Conditions
	Unsatisfactory or Difficult

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COMMERCIAL STATUS

TECHNOLOGY:

Well developed.

SUPPLIERS:

There are a few local suppliers that offer prefabricated systems. Suppliers of commercial compost products are adequate on a mail order basis.

COST:

Compost systems can be constructed on site with minimal material costs of $10 – $30. Commercial systems can cost $30 to $130.

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IMPLEMENTATION ISSUES

FINANCING:

Not applicable.

PUBLIC ACCEPTANCE:

People who enjoy gardening have long been interested in composting. The fact that a compost system requires maintenance deters many people who are not environmentally conscious.

REGULATORY:

Improperly maintained compost systems that attract animals or cause odors can be considered a public health menace. Check local restrictive covenants.

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GUIDELINES

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1.0 Commercially available prefabricated compost bins

Require little or no site preparation.

They are placed at a convenient outdoor location with easy access and low visibility.

Different composting techniques may be used with different prefabricated units. Follow suppliers instructions.

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2.0 Site-built compost area

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.

2.1 Composting Guidelines

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.

Use 3 to 6 inches of coarse materials such as branches, leaves, 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.

2.2 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.

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3.0 Vermiculture

Worms will consume food scraps and paper faster than bacteria.

Dampened newspaper or cardboard scraps are added with food waste.

Kits can be purchased or instructions are available to do it yourself. (see Resources)

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4.0 Suitable Materials

Compostable materials include:

• 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 (use “green”, some seeds may survive);
• grass clippings (will mat without mixing in other materials);
• nut shells,
• hair (very high in nitrogen);
• other (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 cat litter.