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Composting Provides Benefits and Solutions for Local Growers

San Diego County is home to more small farms (less than 10 acres) than any other county in the U.S. and an ever growing number of community gardens, both of which often produce much more organic material than typical residences.  Composting offers solutions for managing large amounts of organic matter and recycles the minerals and nutrients back into the soil.  While the fundamentals of composting remain the same whether it’s a single bin or small loader, different management practices are needed as volumes increase.

According to the San Diego County Farm Bureau, among the county’s 2.6 million residents, are more than 6,000 farmers making their living on 6,565 small farms, 65 percent of which are nine acres or less in size.

The cost of water and land in San Diego County make farming here expensive.  Small to mid-scale composting offers benefits and efficiencies that are worth the investment with improved soil health, crop output and water retention among them. Compost is loaded with organic matter and beneficial soil organisms that improve the health and quality of soil.  Compost saves money by replacing soil amendments that would otherwise need to be purchased and has been proven to significantly increase soil’s water retention capacity.  There are also economic opportunities in producing and selling compost to the community. New State laws encourage composting and other methods that prevent disposal oforganic materials in landfills. 

Beginning on April 1, 2016, Assembly Bill 1826 (AB 1826) mandates that commercial generators of more than 8 cubic yards per week of organics would be required to compost the material, or make arrangements for it to be properly recycled. Organic waste as defined in the law includes the following material: food waste, green waste, landscape and pruning waste, nonhazardous wood waste, and food-soiled paper waste that is mixed in with food waste. These categories represent the largest subsets of organic waste that is currently disposed in California. The mandatory organics recycling law applies to any business, defined as a commercialor public entity (such as a school, hotel, restaurant or hospital) including multifamily residential dwellings (5 units or more), that generates the specified amount of organic waste. 

A business that meets the waste generation threshold shall engage in one of the following organic recycling activities:

  • Source separate organic waste from other waste and participate in a waste recycling service that includes collection and recycling of organic waste.
  • Recycle its organic waste on site, or self-haul its organic waste off site for recycling.
  • Subscribe to an organic waste recycling service that may include mixed waste processing that specifically recycles organic waste.  (Note that a multifamily complex is not required to arrange for recycling services for food waste.)

“With these new regulations, we’re going to need to build composting capacity throughout the county. Farms and community gardens are an obvious place to start,” said Jessica Toth, Executive Director of Solana Center for Environmental Innovation.

Why recycle organic material? 

Organic material in the landfill breaks down without air (anaerobically) and in the process, creates methane gas.  Methane is a greenhouse gas that warms the Earth by absorbing energy and slowing the rate at which the energy escapes to space. Global warming potential (GWP) is a relative measure of how much heat a greenhouse gas traps in the atmosphere. The larger the GWP, the more that a given gas warms the Earth compared to carbon dioxide over that time period. According to the Intergovernmental Panel on Climate Change (IPCC), methane has a lifetime of 12.4 years and with climate-carbon feedbacks a global warming potential of 86 over 20 years.  Methane has a global warming potential more than 25 times greater than that of carbon dioxide.

In response to the new law and to educate San Diegans about the need for small to mid-scale composting, Solana Center is presenting a free Composting Workshop for Farms and Community Gardens on Saturday, April 9, 2016 from 10 AM to 12 PM at the San Diego County Farm Bureau in Escondido, CA. This two hour presentation will give an overview of small to mid-scale composting for those who handle large amounts of compostable materials. Topics covered will include:

  • Composting basics: science, feedstock, site selection, benefits
  • Composting methods: turned windrow, aerated static pile, in-vessel, passive piling
  • Concerns: water and odor management
  • What is AB 1826: current regulations and permitting

A more extensive course will be offered in May-June for those interested in learning more in-depth techniques.  This composting workshop is funded by the County of San Diego.  Pre-registration is required. For questions, contact Diane Hazard, Education Program Manager at (760) 436-7986 x217.

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