Halting and reversing the current loss of biodiversity and habitats will be facilitated by a comprehensive valuation of all nature's contributions to people (NCPs), on which we rely. In this context, we explore the full natural capital value of seeds to reveal how this extends far beyond their economic value associated with mainstream agriculture and forestry. Seeds represent the main assets for nature-based solutions at species (i.e., unlocking neglected species properties and via seed banking) and ecosystem level (i.e., ecological restoration). Challenges remain to enhance their sustainable use in nature conservation and in supporting a sustainable development model. Such advances will depend on the comprehensive valuation of the natural capital value of seeds, which has so far been grossly underestimated. 'Nature's contributions to people' (NCPs), on which we rely, are declining substantially. Plants contribute to a large spectrum of 'regulating', 'material', and 'non-material' NCPs. The natural capital value (NCV) of seeds can be described using a 'total economic value' approach, distinguishing their existence value, direct use, indirect use, and option value. Biodiversity and their NCPs constitute the assets for nature-based solutions (NbS). Seeds represent the main assets for NbS at species and ecosystem level. [ABSTRACT FROM AUTHOR]