On Mother’s Day weekend, a steady flow of customers passed through the doors of Jim Baum’s Marin Community Farm Stand in Forest Knolls.
Conveniently located at a former gas station on the valley’s thoroughfare, the stand offers crates of produce and freezers of meat—along with beer and wine, soaps and preserves, and other goods—five days a week. It’s the flagship location of a business that Mr. Baum, a Brooklyn native with a knack for sales,…