Benefits of Using Compost
On this page:
- Producing Compost
- Overall Benefits of Using Compost
- Key Sectors for Compost Use
- Considerations for Using Compost
- Additional Resources
Producing Compost
Composting diverts organic materials such as food scraps, yard trimmings, wood, and manure that would otherwise be disposed of in landfills or trash incinerators and recycles them into compost, a valuable soil amendment. Producing and using compost provides benefits to the environment, the economy, and communities. Unlike traditional recycling, in which recyclables are shipped abroad for processing, composting keeps materials local, often producing and using compost in the same area where materials are generated. Recycling organic materials into compost and then applying compost to lawns, gardens, farms, parks, and other sites closes the loop from soil to soil, shifts our view of organic materials from a waste product to a valuable resource, and supports a circular economy.
Composting:
- Protects the climate by reducing methane emissions from landfills.
- Reduces waste.
- Recycles organic materials into a valuable soil amendment – compost.
- Recovers nutrients in organic materials and keeps them local.
- Creates green jobs.
- Extends municipal landfill life by diverting organic materials.
Overall Benefits of Using Compost
In the U.S. and around the world, our soils suffer from topsoil loss, degradation, and erosion, which lead to water quality issues and reduced productivity of agricultural and other lands. According to the Food and Agriculture Organization of the United Nations, about 33% of soils worldwide are moderately or highly degraded. Lack of nutrients in depleted soils leads to increased and excess use of synthetic and mined fertilizers – also known as inorganic fertilizers – which are washed by rain into our waterways. Sediment from degraded and compacted soils also runs off, and new soil is not added fast enough to replace lost topsoil. Soils that have been eroded, compacted, and depleted of nutrients and organic matter are less able to support plant growth. Many of these problems can be mitigated by using compost, which adds much-needed organic matter to soil, improves plant growth, conserves and filters water, reduces reliance on inorganic fertilizers, and helps prevent nutrient runoff and soil erosion.
There are many markets and applications for compost, both existing and emerging: agriculture, horticulture, landscaping, gardening, topsoil and sod production, roadside and construction projects, wetlands protection and creation, soil remediation, land revitalization, sports fields and golf courses, ecosystem restoration, sediment and erosion control, and green infrastructure.
The value that compost can provide has enormous potential and can grow with the expanded use of compost across different sectors. Most of the information on this webpage comes from an EPA report, "Environmental Value of Applying Compost: Improving Soil Health for Stormwater Management, Contaminated Site Remediation, Ecosystem Restoration, Landscaping and Agriculture" (2025). Please reference the report for more information.
Soil Health
As defined by the USDA Natural Resources Conservation Service (NRCS), soil health is the continued capacity of soil to function as a vital living ecosystem that sustains plants, animals, and humans. As a soil amendment, compost helps to promote soil health, improving the physical, chemical, and biological characteristics of soil.
Compost is a source of organic matter, providing nutrients and structure to soils. Soil organic matter helps to create stable soil aggregates, which increase soil porosity and makes soil more resistant to being dispersed by wind and rainfall, inhibiting soil erosion. Improved soil porosity and lower bulk density facilitate water infiltration, water percolation, and soil aeration, helping soils absorb and retain more water and providing space for roots to grow and for soil organisms to move and breathe.
Compost application benefits soil chemistry as well, stabilizing the pH of soil and adding nutrients to increase soil fertility. Compost contains essential plant macro- and micronutrients, including nitrogen (N), phosphorus (P), and potassium (K). These nutrients are mostly in slow-release, organic forms which are less prone to run off and cause pollution in water bodies, compared to inorganic fertilizers. Applying compost can help soil retain nutrients and keep soil pH near neutral, which enhances the availability of nutrients to plants.
Compost also increases the organic carbon in soils by adding carbon directly and by increasing the productivity of plants, which in turn add carbon through roots and residues. Finally, compost benefits soil biology by improving the diversity and abundance of beneficial soil organisms, who feed on soil organic carbon and make nutrients available for plants to use.
Water Quality and Water Conservation
Compost is a useful tool to manage runoff and improve water quality. Compost benefits water resources by improving soil health and plant productivity and through use in stormwater management practices. Excess nutrients and sediment in runoff contribute to eutrophication and sedimentation of water bodies, drinking water toxicity, algal blooms, and fish kills. Nutrients from compost are less prone to runoff or leaching because they are released more slowly than nutrients in inorganic fertilizers. Compost also has water filtering capabilities, catching sediment when used in stormwater management practices and green infrastructure, and supporting diverse microorganisms that can break down certain toxins and pollutants.
Compost increases the porosity and lowers the density of soils. When soils are more porous, water can infiltrate the surface and stay in the soil, reducing the loss of soil and nutrients in runoff, and allowing water to percolate downward and recharge aquifers. Using compost can also reduce irrigation needs, helping to conserve water resources. Compost use is a nature-based solution that supports adaptation and resilience to climate-driven changes such as flooding, drought, and shifts in the quantity and quality of water resources.
Climate Change
Creating and using compost is a simple, effective, and scalable way to help reduce carbon in the atmosphere and increase climate resilience in communities. Composting decreases greenhouse gas emissions by diverting organic materials from landfills. The use of finished compost can reduce emissions by sequestering carbon in soils and by partially replacing carbon-intensive products used in agriculture and landscaping, like synthetic nitrogen fertilizer and peat. Adding compost to soil increases the capacity of soil to absorb and retain water, which improves resilience to drought and reduces risks from flooding. Compost can also support tree growth, reducing the heat island effect in cities by providing shade and evapotranspiration.
Key Sectors for Compost Use
Compost can be used in a variety of settings and sectors of the economy where soil health, plant growth, water quality and conservation, and climate resilience are important goals. The environmental benefits of using compost are numerous. Increasing the use of compost can drive the demand for more compost to be produced, which can encourage the diversion of organic materials from landfills to composting, avoiding methane emissions from landfills, supporting a circular economy, and creating green jobs throughout the process.
For more information on the value of applying compost in the sectors outlined below, check out EPA’s report, The Environmental Value of Applying Compost.
Green Infrastructure and Stormwater Management
Stormwater runoff is one of the biggest threats to clean water in the U.S. When water runs off roofs, parking lots, paved streets, and physically disturbed or compacted soils (e.g., from construction of roadways and buildings), it picks up trash, oils, bacteria, heavy metals, nutrients, and sediment, and delivers them untreated into streams, rivers, lakes, and coastal waters. Stormwater management best practices aim to prevent or reduce flooding and pollution associated with runoff. Green infrastructure practices use nature-based solutions, such as compost and vegetation, to treat and soak up stormwater runoff.
Compost helps to “keep rain where it falls” by improving the infiltration rate and water-holding capacity in soils and in green infrastructure systems such as bioswales and rain gardens. These systems increase the volume of stormwater captured and absorbed, reducing runoff and erosion. Compost also filters pollutants from stormwater when it’s incorporated into soils or used in bioretention media, compost blankets(pdf) (887 KB), compost berms (pdf) (1.2 MB), and compost filter socks (pdf) (825 KB). For example, the City of Seattle’s Street Edge Alternative Project infiltrated street runoff into vegetated bioretention cells with soils enhanced by compost, and street stormwater runoff was reduced up to 99 percent, improving water quality.
Applying compost can help to revitalize soils that have been compacted or disturbed during construction projects. Compost is particularly valuable for revegetation, which helps keep soil in place and reestablishes and maintains a healthy ecosystem. Compost-based practices used on their own or in combination with conventional methods—such as hydroseeding or topsoil treatments—can be more effective in revitalizing soils than conventional methods alone. However, because compost is a source of nutrients, potential nutrient saturation and transport should be considered when using compost blankets and compost-based bioretention media.
Learn about EPA’s menu of stormwater best management practices for the National Pollutant Discharge Elimination System (NPDES), which includes several compost-based practices.
Contaminated Site Remediation
Through its ability to bind contaminants and reduce their mobility within the soil, compost enhances the remediation of sites contaminated by harmful substances including heavy metals, petroleum products, and salts. Compost can reduce the bioavailability of metals and increase the success of revegetation efforts on sites where plants may be sensitive to contamination.
Compost works on contaminants in different ways, such as changing the pH of soil or boosting the diversity and quantity of soil microorganisms. For example, compost can help shift the pH of soil toward neutral, at which point aluminum ions bind to organic matter and become immobilized in the soil. Compost with high iron content can help to immobilize lead and arsenic, two common contaminants in urban soils. Adding compost can also support microbial communities capable of breaking down toxic organic compounds in soils such as pesticides, petroleum products, and polychlorinated biphenyls (PCBs). This is known as bioremediation (pdf) (939 KB). Finally, compost supports the growth and improves the survivability of plants used for phytoremediation (pdf) (866 KB) (using plants to help clean up contaminated environments).
The effectiveness of compost in helping to remediate contaminated soils depends on many factors, including the type and amount of contamination, type of soil, properties of the compost, application rate, and more.
Learn more about compost for land remediation in EPA’s paper, The Use of Soil Amendments for Remediation, Revitalization and Reuse (pdf)(1.68 MB)(2007).
Ecosystem Conservation and Restoration
Compost can be used in a variety of ecosystem restoration and conservation projects. The main benefit of compost in these applications is the associated improvements to soil health, water quality, and water conservation. Because compost is rich in organic matter, it closely resembles wetland soils and can be used to restore wetland ecosystems, many of which are significantly impacted by human activities. Compost also helps to revegetate disturbed and degraded soils, speeding the process of rehabilitating impacted sites.
Notably, compost can also support ecosystem recovery following wildfires. The risk of wildfire, particularly in the western U.S., is increasing with the changing climate. Where wildfires have damaged soils, compost use improves soil health and vegetation establishment, accelerating the recovery of fire-damaged lands and supporting the restoration of the natural ecosystem. Compost and vegetation help reduce runoff, soil erosion, and the risk of contamination to drinking water supplies from ash and sediment.
Agriculture and Landscaping
The use of compost in agriculture and landscaping is well-established, as it boosts crop yield and supports plant health. Compost promotes plant growth by improving the health of soils, enhancing fertility, increasing water absorption and retention, and boosting beneficial microbes that suppress plant pests and diseases. Importantly, compost provides organic matter to soils. Worldwide, soils have been depleted of organic matter due to human activities such as intensive agricultural practices (e.g., plowing and tilling), land use change (e.g., deforestation), and development.
Compost provides essential plant nutrients -- N, P, and K -- offsetting the need for synthetic and mined fertilizers like ammonia and superphosphates. These fertilizers are carbon-intensive to produce, and their overuse can result in nutrient pollution in surface and ground water. Using compost in place of these fertilizers can reduce the risk of nutrient runoff. However, compost does not always contain high enough concentrations of nutrients in plant-available form to satisfy the needs of crops, such as many annual crops. Therefore, sometimes conventional inorganic fertilizers must be used in addition to compost, but in smaller quantities than if no compost was used at all. Because compost releases nutrients slowly, continued addition of compost can build up nutrient reserves in soils, reducing the need for additional fertilization over time.
Considerations for Compost Use
Compost might not always be the best option for a particular site, soil or project. Factors like the feedstocks in compost, how the compost is made, the compost application method and rate, the type of soil receiving the compost, and the season, climate, and terrain of the site where compost is being applied can all affect the value of using compost.
Different composting feedstocks (organic materials used in composting) provide different benefits and challenges. For example, food scraps are an abundant and nitrogen-rich feedstock, but food scraps from some sources may introduce contaminants to a composting system. Similarly, the characteristics of finished compost vary and can be more beneficial for certain uses than others. For example, stormwater management and erosion control projects often benefit from compost with a high carbon-to-nitrogen (C:N) ratio and coarse texture, but these compost characteristics would not be as beneficial for use in a vegetable garden.
Here are some things to think about when considering using compost:
- What are the goals of your project and how can compost support those goals? For example: increasing soil fertility, reducing soil erosion, or sequestering carbon.
- What are the characteristics of the compost or compost-based soil blend you need? For example: nutrient content, C:N, ratio of compost to other materials in the blend, texture of compost (coarse, fine, or somewhere in between).
- Does the compost meet the U.S. Composting Council’s Seal of Testing Assurance certification standards or other quality standards or specifications, if required or preferred?
- What are some best practices for using compost in your industry/sector? Is there guidance you can follow?
Additional Resources
From EPA
- Environmental Value of Applying Compost (report from EPA).
More resources are available on other EPA composting webpages:
- Composting at Home – learn about different ways to start composting at home.
- Approaches to Composting – learn about different models and methods of composting, as well as some basic composting science.
- Community Composting – learn about this decentralized model of composting.
- Composting Homepage – learn about the benefits of composting, plus find resources on composting policy and legislation.
- Start a Composting Program – learn about establishing or expanding composting in your area.
Check out these EPA webpages for more on stormwater management, green infrastructure and land revitalization:
- Soak Up the Rain: The Benefits of Green Infrastructure.
- NPDES Stormwater Management BMPs.
- Land Revitalization Program.
- Tools for Ecological Land Reuse.
From Other Organizations
- Building Healthy Soil (pdf) (2.8 MB) (guide from Seattle Public Utilities).
- Soil Health Institute.
- Building Soils for Better Crops: Ecological Management for Healthy Soils (pdf) (13.8 MB) (Handbook from USDA & SARE).