Always, good science has been the goal, even when the solutions seemed low-tech. The procedures described here for long-term storage of orthodox seeds are based on those developed by Kew's seed bank at Wakehurst Place. Once seed has been collected, the basic sequence of events is to dry the seeds, clean and count them, and then package them for long-term frozen storage. Developing germination procedures for each species is important. Viability of the seed should be tested at various stages, and not assumed.
Most seeds fall into two discrete categories.
Orthodox seeds can survive drying to such a low moisture content that freezing will not kill them because no ice crystals are formed. Recalcitrant seeds such as acorns, and fruits of many tropical trees, are much more demanding and cannot survive drying, and cannot be stored frozen. Low-tech seed banking is thus only for orthodox seeds. The primary determinants of how long stored seed remains viable are seed moisture level and storage temperature. The optimal moisture content for long-term storage is a complex mix of many things, including the chemical composition of the seeds.