A seed network and its short term seed bank may provide a temporary sanctuary for local seed varieties in your region. However is it best to keep varieties growing in gardens, given to new members and saved each year so they adapt to climate changes and seeds are therefore from last harvest therefore fresh and produce vigourous seedlings.
Vegetable seeds in storage get stale with fungus attacks and eventually becomes infertile.
Community organisations themselves do not need to store seed for long term as it become almost always a seed morgue and time consuming in regular viability tests. However individual members may choose to store their seeds in a freezer for safe keeping. The aim of a local seed network and its short term holding seed bank is to keep seeds for a few years only to provide seeds to news members. The best method so far is to hold seeds in each member gardens and private storage jars or bottles. Seed in community seed bank need to be germination and vigour tested regularly to make sure that no one is give an old seed that has lost fertility and vigour and its disease resistance as older seeds get infected by fungus if not dried enough.Seed have a definite life and health span (Stored seeds last one season to several years according to ambient temperature and seed moisture). Seeds that do not germinate are not fit to eat either.
However in farming communities producing cereals for subsistence and who are beginning to collect local varieties then a seed bank is very useful to hold safely growing numbers of varieties and larger quantities of grain in hessian bags (that is to distribute grains to new members (usually one kg is given to each person who then return 2 kg), These grains may be numerous types of barleys, rices, wheats species, but also lesser know low rainfall millets of many species, genera and varieties (teff, ragi, sorghums and millets) The community seed banks seedsavers works with in India are independent and mostly run by women. They all function as social meeting place, training and seed storage. In India they can be in hindu temples.
In Australia seedsavers do not need to store seed for the long term as seed have a definite life and health span and seeds have no guaranties to remain viable if not in the ultimate conditions which is rarely the case, (seeds in storage will last from one season to several years according to seed moisture and temperature best at 5% moisture which is hard to obtain).
A seed network and short term seed bank provide only a very temporary sanctuary for local seed varieties in one’s region. Seeds are best growing in gardens and saved each year so they adapt to climate changes. If in a a school, start saving seeds by setting up a seed garden to save seeds of local origins. If you are in a community, start a community seed network, and a short term community seed bank.
In other words, a community seed bank is in fact another name for a network of seed savers. Each member collects seeds from their gardens and farms, re-grow them out and pass them onto other to make sure that local seed variety is not lost but multiplied by many for security and the fun of giving.