The primary ex situ strategy for plant conservation, seed banks can provide material for research or reintroduction without harming fragile wild populations. This strategy is a complement to, not a substitute for, protecting plants in the wild.

Priority for accession into the Society's seed bank is given to species that exist at only a few sites, are declining rapidly, or are not currently protected. Society staff and volunteers collect seed from as many individuals as possible without damaging the reproductive potential of the population. They clean and dry the seed and store it in a freezer at -18°C. The viability of the stored seed is tested at regular intervals.

The seed bank is under the direction of the Society's Conservation Director with an advisory board made up of NEPCoP members.