A variety of different containers are used to keep seeds dry within the cold rooms of Kew’s Millennium Seed Bank.
Containers full of seeds in cold storage
After final drying, seed collections are packaged into airtight containers within the drying room and then transferred to the cold rooms for long-term storage at a temperature of -20°C.
All collections are divided into a 'base' collection that is infrequently accessed and an 'active' collection from which samples are taken periodically for viability testing and seed distribution. The base collections are always double packaged to reduce the risk of moisture ingress to an absolute minimum. In both cases silica gel indicator sachets (previously equilibrated with the dry room conditions) are placed inside the containers and periodically checked for evidence that moisture has entered the containers. All collections are carefully labelled with moisture-proof labels.