Compost Process
Photos of the Composting Process
Jepson Prairie Organics (JPO) processes the organic material it receives in ninety days. The material comes from two main sources: food scraps generated at restaurants, hotels, markets, and coffee shops in San Francisco and Oakland and from yard trimmings generated in Dixon and Vacaville.
Presently, Jepson Prairie Organics processes approximately 5,200 tons of food scraps per month from San Francisco and Oakland and 2,000 tons of yard trimmings per month from Dixon and Vacaville. The two feedstocks are fed into an industrial sized grinder and mixed to attain a recipe of physical and chemical characteristics that are ideal for microbial decomposition.
The blended material is mechanically pushed into our adopted composting system, the Ag-Bag Composting Technology, with an in-vessel, forced aeration composting process. The bagging system fills a 200-foot plastic pod with feedstock while laying out two 4" perforated pipes inside the pod in order to maintain oxygen levels sufficient for degradation. The material remains in the Ag-Bag pod for 60 days during which time the composting material is monitored for temperature and oxygen levels. These measurements ensure that proper temperatures have been reached and maintained in order to eradicate undesirable microbial life. After the composted material has undergone the Ag-Bag process, the compost is placed in windrows.
The windrows help age or "cure" the compost. During the curing period, the windrows are moisture conditioned and agitated with a windrow turner, which acts to reduce the particle size of the compost material and reintroduces oxygen into the pile. The compost cures for 30 days, at which point it is ready to be put through a trommel screen.
The trommel screen separates the larger pieces from the finished product, and the result is a 3/8' finished compost. Our compost contains levels of nitrogen far superior to those of typical green waste compost due to the incorporation of the Bay Area's diverse feedstock featuring food scraps.
Compost Process for Vineyards
Vintage Production
Vineyard managers are excited about the nutrient-rich compost made from San Francisco food scraps.Every day San Francisco sends more than 300 tons of food scraps and other suitable materials to Jepson Prairie Organics. Companies like Redi Gro that blend and bag soil for sale at landscape supply yards were the first to use the compost. Farmers, commercial nurseries, and landscape supply yards immediately liked the finished compost because of its high levels of nitrogen and other nutrients.
The compost is listed by the Organic Material Review Institute as appropriate for use on organic soils.
Food Scraps to Fine Wine
Vineyard managers use our compost; made from a diverse feedstock including food scraps from San Francisco's finest restaurants, to recondition their soil after the harvest. Compost provides a natural way to improve growing conditions, and vineyard managers are looking for new ways to provide healthy environments to grow stronger vines and better grapes.
Vineyard Compost Images
Click on any of the following images to enlarge.
Food scraps provide a diverse feedstock to make rich compost filled with nutrients that benefit the soil.
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A pile of rich compost is about to be applied between rows of vines at Madrone Vineyard, Sonoma County.
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Madrone Vineyard applies a layer of compost rich in nitrogen and other nutrients that benefit plants.
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A spreader applies our rich, black compost between rows of vines at Domenici Ranch, Sonoma County.
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A quarter shows the scale of a fresh layer of compost applied between rows of vines at Madrone Vineyard.
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More than 100 vineyards in Northern California use Four Course Compost to improve soil structure and return nutrients to the root zone.
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