In 1975, the Missouri homesteaders Kent and Diane Ott Whealy launched True Seed Exchange (later Seed Savers Exchange), a network of ‘serious gardeners’ interested in growing and conserving heirloom and other hard-to-find plant varieties, especially vegetables. In its earliest years, the organization pursued its conservation mission through member-led exchange and cultivation, seeing members’ gardens and seed collections as the best means of ensuring that heirloom varieties remained both extant and available to growers. Beginning in 1981, however, Kent Whealy began to develop a central seed repository. As I discuss in this paper, the development of this central collection was motivated in part by concerns about the precariousness of very large individual collections, the maintenance of which was too demanding to entrust to most growers. Although state-run institutions were better positioned to take on large collections, they were nonetheless unsuitable stewards because they placed limits on access. For seed savers, loss of access to varieties via their accession into a state collection could be as much an ending for treasured collections as total physical loss, as it did not necessarily enable continued cultivation. As I show here, these imagined endings inspired the adoption of a new set of conservation practices that replicated those seen in the formal genetic conservation sector, including seed banking, cold storage and safety duplication.