In general the banking of seeds has considerable advantages over other methods of maintaining diversity such as ease of storage, economy of space, relatively low labour demands and, consequently, the capacity to maintain large samples at an economically viable cost. Seeds are a convenient means of long-term storage of genetic diversity as the samples are small in size, easily handled, require low maintenance and frequently remain viable for long periods. In general, conditions of low temperature and desiccation allow seeds to maintain viability. Seed banks take up little space, but need to be maintained at low temperatures, with a requirement for germination tests, growth trials and regeneration.
For the garden our seed bank is a fundamental collection, that allows us to maintain the yearly cycle of propagation and planting for short lived annuals and perennials, facilitates the exchange of material with other gardens and researchers, and allows us to store wild-collected seed from expeditions. In the seed bank, cleaned dried seed is kept in sealed jars at five degrees which enables us to keep seed viable for between 5 to 20 years. Different seed can be stored for different amounts of time in these conditions, for example, some plants produce many small seeds adapted to persist for a long time in soil. When correctly dried and stored seeds such as these can remain viable for a very long time. Other seed may not be so long lasting so will need to be sown and recollected more frequently.