California Department of Resources Recycling and Recovery (CalRecycle) 

Agricultural Demonstration Projects

Compost in Commercial Mushroom Production

Developing Technology to Grow Mushrooms from Recycled Urban Waste and Vermicompost

(See the UC Davis Cooperative Extension's site on this project).

Green highlighted words indicate definitions and links to the glossary section.

The University of California Cooperative Extension of Santa Clara County Agricultural Research Program (UCCE-SCL) previously researched alternative substrate materials for mushroom cultivation. In this bench scale, preliminary research, UCCE-SCL determined that composted yard trimmings and composted wood-overs have high potential as substrate base for the production of oyster mushrooms (Pleurotus pulmonarius and P. ostreatus). The substrate base used in current mushroom production is specialized compost made primarily from nonwaste sources. The UCCE-SCL also determined that vermicompost produced from food scraps and paper waste has characteristics similar to those of peat moss. Peat moss is the main material used as the casing layer in commercial white button mushroom (Agaricus bisporus) production and is a costly "non-native" and "nonrenewable" input.

Description of the Growing Process

Del Fresh Produce website provides a good description of how mushrooms are commercially produced and how specialty compost is made and used in the process. (Note: The inclusion of this company does not constitute an endorsement by the California Department of Resources Recycling and Recovery (CalRecycle). CalRecycle does not endorse specific companies.)



The UCCE-SCL, in partnership with CalRecycle, the City of San Jose, Royal Oaks Mushrooms, Countryside Mushrooms, Browning-Ferris Industries, Z-Best and Zanker Road Landfill, and the County of Santa Clara was awarded a three-year grant from the California Department of Food and Agriculture’s Buy California through the University of California Specialty Crop Research Program for $109,398 to explore the commercial use of wood-overs and vermicompost in large scale mushroom production.

The research consisted of two independent experiments:

  1. Vermicompost and composted wood-overs will be combined in various formulas as substrate base to test the response of oyster mushroom production.
  2. Vermicompost made from several formulas, including the recycling of mushroom stumps, food scraps and paper waste, will be used as casing (peat moss substitute) to test the response of white button mushroom production.

Picture of a mushroom cropWhite button mushroom production at the Countryside Mushroom facility in Gilroy, California.

Pile of wood-overs used for mushroom production.Grant participants discussing the merits of wood-overs at the Z-Best compost facility in Gilroy, California.


UCCE-SCL, in coordination with cooperators developed and disseminated educational materials, preliminary findings, and final results of the project through publications, presentations in conferences, open field days, and workshops; organized and hosted a field day/year; and organized workshops and provided educational materials on recycling, composting and vermicomposting to workers at growers’ facilities.

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Last updated: August 13, 2010
Organic Materials Management