Uses of compost

Additional recommended knowledge

Daily Visual Balance Check

Daily Sensitivity Test

Safe Weighing Range Ensures Accurate Results

Regulation in the US

Class A and Class B standards were originally developed to manage the processing and beneficial reuse of biosolids. However, some American states now require all composts, including yard waste, to be processed according to federal protocols for pathogen and vector control.

Many compost manufacturers also participate in the U.S. Composting Council's Seal of Testing Assurance (STA) program and can provide customers with a detailed laboratory analysis that includes information on macro and micronutrient content, maturity, salt content, pH, and other important quality indicators.

Agriculture

Open ground

For growing wheat, corn, soybeans, and similar crops, compost is broadcast across the top of the soil using spreader trucks or spreaders pulled behind a tractor. Usually, the layer is very thin (one-eighth to one-quarter inch or 3-6 mm)) and worked into the soil prior to planting. However, application rates of one inch or more are not unusual when trying to rebuild poor soils or control erosion.

Plasticulture

Strawberries, tomatoes, peppers, melons, and other fruits and vegetables are often grown under plastic to retain moisture and control weeds. Compost may be banded (applied in strips across the field) and worked into the soil prior to bedding and planting, or the compost can be applied at the same time the beds are constructed and plastic laid down.

Compost has also performed well as a substitute for methyl bromide, an agricultural fumigant once commonly used in plasticulture production, but now being phased out by international treaty.

Transplant mix

Many crops are not seeded directly in the field but are started in seed trays in a greenhouse. When the seedlings reach a certain stage of growth, they are transplanted in the field. Compost can be used as an ingredient in the mix used to grow the seedlings, but compost is a concentrate and should not be used as the only planting substrate. The crop to be grown and the seeds' sensitivity to nutrients, salts, etc. dictates the ratio of the blend.

Bioremediation

Compost may be used in the remediation or neutralization of soil and water contaminants like gasoline, diesel fuel, transformer oil, and other toxic or hazardous materials. Contaminants may be treated in situ or transported to a treatment facility where contaminated soil and/or water is blended with compost. Ideally, the compost has been prepared especially for bioremediation of the target compound.

For spill response, compost is used as an absorbent to contain and collect liquids prior to transport to a remediation facility.

Erosion control

Topsoil loss is a serious planetary issue. The use of compost to control sediment run-off and fight erosion is a relatively new technology, now being adopted by state transportation departments, developers, farmers, and other major disturbers of soil as another tool to reduce topsoil loss.

Compost blankets

A layer of compost spread over a disturbed area of soil is called a compost blanket. With a water-holding capacity greater than 100 percent, compost is not tilled into the soil but remains on the surface to temper the impact of rainfall. Even small amounts can help, but typical recommendations call for a two-inch (5 cm) layer to insure adequate surface coverage. The blanket can also be vegetated.

Compost berms and filter socks

Compost berms and socks are used alone or in conjunction with compost blankets to mitigate the impact of high volume water discharges and flows. Compost berms are more aesthetically pleasing than silt fences and eliminate the need to remove the berm when the project is complete. Over time, a compost berm simply biodegrades and returns to the earth. As the name implies, a compost sock is a mesh tube stuffed with compost. Socks stand up better to heavy equipment, can be anchored in place, and are easily removed/reused. If a biodegradable fiber is used for the sock, it can also be left in place to biodegrade.

Gardens & landscaping

Bedding mixes. Compost can be mixed with sand, clay, aged sawdust, and other materials to create an enriched mix for landscape beds or raised-bed gardens. Compost should be no more than 30 percent of the total mix. Use a mature compost to avoid competition with plants.

Container mixes

Like bedding mixes, compost is a beneficial ingredient in potting media, but use no more than 30 percent in the total mix. In many cases, it can be used as a substitute for peat moss. Depending on the NPK content, compost can also reduce the need for chemical fertilizers.

Foundation plantings

Excavated areas around the foundation of new buildings are backfilled when construction is complete, but these planting zones may contain rubble, residues of toxic chemicals, and other undesirable substances. Removing the backfill and replacing it with a compost mix will improve soil structure and give foundation plantings a healthier start.

Mulch/weed control

Two or more inches of compost can be used alone or in conjunction with conventional mulch products to keep root zones cool, conserve moisture, and act as a slow-release fertilizer. For a weed barrier, double or triple the depth of the compost or place on top of a thick layer of newspapers or a geomembrane.

Trees and shrubs

Mix compost with the native soil and use as backfill when planting trees and shrubs. Seasonally, top dress with compost to the drip line and rake into the soil.

Turf and pasture management

To establish new turf areas (lawns, recreation fields, golf courses), apply compost prior to seeding or sodding and work into the soil. Seasonally, top dress with compost and rake into the soil. Some turf farms also use compost, growing grass in a couple of inches of the material to prevent topsoil loss.

Special uses

Constructed wetlands

Compost is used as a planting media for constructed or artificial wetlands.

Landfill cover

When a landfill cell is filled, compost can be added to the soil used to cap the cell to encourage vegetation and reduce erosion.

Streambank restoration

Erosion along streambanks threatens trees and property, but the use of compost can not only restore functionality and beauty to riparian zones, but also mitigate future damage.