Compost and Mulch Producers

Nearly 170 businesses in California produce compost and mulch. An extensive survey conducted in 2008 provided the CIWMB (now known as the Department of Resources Recycling and Recovery, or CalRecycle) with key information on the number of producers, feedstock sources, products, and markets for compost and mulch. CalRecycle provides regulatory oversight and marketing assistance to compost and mulch producers.

Permits and Regulations

Most commercial compost producers are subject to regulation in California. Please see the Fact Sheet on Solid Waste Facility Permits for additional information. Certain aspects of mulch operations are also regulated. Local Enforcement Agencies (LEA) oversee the permitting and oversight of composting and mulch operations. The composting regulations can be viewed on CalRecycle’s website.

  • Permit Tasks: Identifies the permit process tasks and permit application elements that apply to each type of permit.
  • Permit Toolbox: Provides online permit tools and resources.

Facility Operation Resources


CalRecycle conducts compost and mulch outreach activities throughout the state. These activities include exhibiting at agricultural and landscaping industry trade shows and workshops.

Product Quality

The quality of a compost product can be determined by testing for specific characteristics, including pH, soluble salts, nutrient content, organic matter, maturity, and stability. Appropriate ranges for specific characteristics depend on the type of application. Several resources are available to assist compost operators and purchasers in determining the suitability of a compost product for a specific type of application.

Infrastructure Surveys

CalRecycle’s August 2010 report, Third Assessment of California’s Compost- and Much-Producing Infrastructure–Management Practices and Market Conditions provides the third comprehensive survey of California’s organics materials management industry. The survey was conducted to update the information from two previous reports, Assessment of California’s Compost- and Mulch-Producing Infrastructure (2001) and Second Assessment of California’s Compost- and Mulch-Producing Infrastructure (2003). These reports have helped CalRecycle better understand market dynamics and assist businesses and local jurisdictions in their efforts to market organic materials. The reports provide information on the number of operating compost and mulch producers, quantities and types of feedstock, product quantities by type and region, and feedstock quality. The 2010 report compares results to the previous reports and includes information on how organics processing facilities are responding to regulatory challenges. Key findings for 2010 include:

  • 130 operating entities: 115 composters and 115 processors/chippers and grinders.
  • Almost 9.3 million tons of material processed into 13 million cubic yards of products.
  • Major product categories: compost (4.3 cubic yards), boiler fuel (2.9 cubic yards), Alternative Daily Cover (3.0 cubic yards), and mulch (1.6 cubic yards).

While California’s compost- and mulch-producing infrastructure increased in the past decade, the majority of facilities process under 49,000 tons/year of mostly woody or green material.

Compost and Mulch Producer/Supplier Resources

CalRecycle offers free advertising to compost and mulch producers on a Web-searchable database and is working to increase the number of registered producers.

Various research projects and demonstrations are also being supported by CalRecycle to help research and promote the benefits of compost and mulch.

Other Resources


(916) 341-6809 (LEA support, outreach)

For more information contact: Organic Materials,