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 property “stays in agriculture” and “still has the potential to provide food and educate.” Before listing the farm, owner Warren Weber, who could not be reached for comment by press time, worked with the Trust for Public Land in an attempt to find a nonprofit or public agency buyer. The effort ended in December. “The stars did not align,” said the organization’s California director, Sam Hodder. Star Route Farms, begun by Mr. Weber in 1974, drew a visit from Prince Charles in 2005. While it has been held up as a paragon of organic agriculture, it has also seen some controversy: it was once involved in a lawsuit with the Tomales Bay Association, which sought to turn five agriculturally zoned acres of the farm into wetlands. The farm prevailed in an appeals court in 2007.