What is a Seed Bank?

A seed bank is a facility used to store seeds of various crops and wild plants, in an effort to maintain biodiversity. These structures can be found scattered all over the world, established by governments and organizations concerned about crop diversity. The Global Crop Diversity Trust proposed in 2007 that an Arctic seed bank be established, to preserve seeds of vital crops in safe bunker conditions in the event of catastrophic events. Many nations agree, because they are concerned about damage to global seed receptacles due to political and environmental developments.

Globally, approximately 150 crops make up the majority of the food grown and consumed by humans. These crops have numerous subtle variations which make the plants more drought tolerant, frost resistant, nutritionally valuable, or easy to harvest. Farmers tend to cultivate crops in a way which will increase desirable traits at the expense of variation, and many biologists are concerned about the diversity of global crops. A seed bank is established to save samples of crop variations, so that they do not disappear forever.

Biodiversity is important for crops for a number of reasons. The first is that a crop could be highly vulnerable if one variety was heavily cultivated. A disease which evolved to attack the crop could devastate stocks worldwide if farmers all grew the same variety. If a seed bank had not been established, the crop might actually disappear, because no new plants could be grown. Hybridizing also makes crops stronger, and farmers are encouraged to breed back to wild versions of a crop to increase its hardiness on the farm, or to cross it with a different variety.

In a seed bank, samples of all the variations on a crop are kept in cool conditions so that they do not sprout or become damaged. Periodically, the seeds are used to grow plants, which are used to produce fresh seeds for the bank to ensure that the seeds will be viable if they ever need to be used. In addition, cultures of plants which do not readily grow from seed are kept in case they are needed. This is especially important with “orphan crops” such as cassava and taro, which make up a huge part of people's diets in some part of the world. Damage to these crops could have a very serious impact which can be averted by a seed bank.

A seed bank also preserves important pieces of regional heritage, such as rare and unusual crop varieties which are not viable commercially. A growing number of crops are cultivated for size, ease of harvesting, and shipping ability, at the cost of biodiversity and taste. A seed receptacle preserves antique varieties of a crop, and many biodiversity organizations also encourage farmers to grow heritage and heirloom crops on parts of the farms so that they do not die out.

Seed banks serve as repositories for preserving genetic diversity of plant species, which is crucial for food security and ecological stability. They store seeds under controlled conditions to ensure their viability over long periods, enabling future generations to access a wealth of genetic material for agriculture, restoration, and research purposes.

Seeds in a bank are typically dried to a low moisture content and kept at cold temperatures, often below freezing, to slow down their metabolism and prolong their viability. According to the Royal Botanic Gardens, Kew, this can extend their life for decades or even centuries, depending on the species.

While most seeds can be stored, some, known as recalcitrant seeds, do not tolerate the drying and freezing process. These include seeds of many tropical plants and certain fruits like avocados and mangos. Seed banks focus on orthodox seeds, which can be dried without damage and remain viable when frozen.

The Svalbard Global Seed Vault, located in Norway, is the largest of its kind. It acts as a backup facility for the world's crop diversity with the capacity to store 4.5 million seed samples, safeguarding them against global crises, natural disasters, and loss of biodiversity.

Seed banks are vital for conserving plant biodiversity by preserving seeds from different plant species, including rare, endangered, and native varieties. They provide a resource for reintroducing plants into the wild and for breeding programs aimed at developing resilient crop varieties to adapt to changing environmental conditions.

While seed banks primarily serve researchers and conservationists, some, like the Millennium Seed Bank in the UK, offer educational resources and public engagement opportunities. They may provide seeds for restoration projects and collaborate with community seed libraries, making a portion of their collections available for broader use.