The oldest continually certified organic farm in California is on the market with a $12.5 million asking price. The 100 acres that comprise Star Route Farms in Bolinas includes four potential building sites, farm buildings, a pond and riparian rights to Pine Gulch Creek, according to the real estate listing. Constance Washburn, director of education for Marin Organic who also worked with the Marin Agricultural Land Trust for 17 years, said she hopes that the…