AS a child, Peg Lotvin used to watch her father, Hank, head out into his garden every fall on a mission. After setting aside part of the bean harvest for his neighbor Flossy, who was reputed to make the best baked beans in all of Ghent, in New York’s Hudson Valley, he would select the largest, heartiest beans from the crop and put them up to plant the next year.

More than 60 years later, Ms. Lotvin, the former director of the town library in Gardiner, N.Y., and others throughout the Northeast are still growing Hank’s X-tra Special Baking Bean. The preservation and propagation of the ghost-white bean have occurred thanks in part to a former colleague of Ms. Lotvin’s at the Gardiner Library named Ken Greene, who founded a group called the Hudson Valley Seed Library three years ago.

In structuring the venture, which aims to be a center for regional heirloom seeds, Mr. Greene chose the library model he knew well: the members of his group receive seeds each spring and then are encouraged to “return” the seeds from the mature plants in the fall.

It was also at the Gardiner Library that he first became concerned about biodiversity. “I checked out stacks and stacks of books about agriculture,” he said. In fact, Mr. Greene’s venture was born at his small-town library. It already lent fishing poles to residents, and Mr. Greene saw no reason not to do the same with seeds.