Tampa Bay's oldest farmers' market and community supported agriculture business is shutting down after 26 years in business. Sweetwater Organic Community Farm is no longer running its weekly Sunday market nor providing shares of produce to members.

"We do not feel we can continue in good conscience to not keep our promises to our members," the board of directors wrote in a memo Monday. It cited "a convergence of circumstances" taking a toll on the business.

Executive director Yvette Rouse and board members did not return calls Monday. According to Sweetwater founder Rick Martinez, members will be reimbursed for the remainder of the season, and fruits and vegetables produced on the farm for the rest of the season will not be wasted but go to already identified recipients.

"Right now, we're looking at some partnerships to restart the season next season. We weren't able to find the magic formula," Martinez said. "I'm speaking as an individual and the founder, because I'm no longer on the board, but the board of directors has decided to sell the farm."

Martinez started Sweetwater in 1993 and in 1995 it became a formal non-profit community-based organization formed to educate people about the benefits of organic gardening, while instilling the importance of community involvement.

The farm included three acres owned by Martinez and almost three other leased acres north of Hillsborough Avenue, all of it farmed without chemical fertilizers or pesticides. It introduced Tampa Bay consumers to the idea of purchasing an annual share of a farm (in recent years that amount has been between $475 and $1,200) and getting a weekly allotment of fruits and vegetables. Initially there was one paid full-time farm manager and a whole lot of volunteers, many using sweat equity to defray their share price. Sweetwater has since become a destination for "eco travelers," with many interns and international visitors volunteering their efforts.

Since its early years, the non-profit has purchased the land on which the farm sits. It has become a regular destination for student field trips, and a major part of Sweetwater's mission is educational programs and farm workshops. According to the memo from the board, those educational programs will continue through April.

Martinez stepped down at Sweetwater five or six years ago to pursue his other career in organic consulting and auditing. Sweetwater's board says they are "actively marketing Sweetwater for sale to organizations with a similar mission or commitment to organic farming/living in order to repay outstanding loans/shares/expenses."

It's unclear just who that might be at this point. The Sindlinger family, which owned Gateway Organic Farm in Clearwater, ceased production due to disputes with neighbors a couple years ago; Mehmet Öztan owned Two Seeds in a Pod farm and heirloom seed company until recently when his family moved to West Virginia. Farming in the Tampa Bay area has proved tricky in recent years, with many acres of what was once farmland being developed and repurposed.

Contact Laura Reiley at lreiley@tampabay.com or (727) 892-2293. Follow @lreiley.