The articles in this special issue contribute to our understanding of the historical emergences and presentday functioning of various modes of conserving plant genetic diversity in seed banks. Exploring both crop plant and wild species conservation at different times and scales, the papers examine how various actors articulate their role in stewarding plant life for the future as seeds. They reveal seed banking and its corollary, seed saving, as responses to uncertainty, which do not resolve this condition but instead generate new ambiguities and new uncertainties.