Seed Bank

A seed bank is a store of planting seed saved from a grower's own crops rather than bought each season. What makes it work is not the shelf but the cycle around it: grow, choose the plants worth keeping, dry and clean their seed, store it, test that it still sprouts, and regrow it before it fades. The shelf is only where the cycle pauses. A collection that stops moving becomes an archive of dead seed that still looks like stock.

Two things decide how long seed lasts and they work together: how dry it is and how cold it is kept. Orthodox seed, the ordinary kind that tolerates drying, keeps best at 4 to 8 percent moisture, and from there every drop of about 5 degrees C (9 degrees F) in storage roughly doubles its life, while every extra 1 percent of moisture roughly halves it. An airtight jar with a drying sachet therefore only helps once the seed inside is already dry; sealing damp seed traps moisture against it and does more harm than a paper envelope. Some seed cannot take the treatment at all: oak, chestnut and other nut and fruit-tree seed is killed by drying and chilling, and must be kept moist and sown within months.

The other half is genetics. Seed saved from a hybrid does not breed true, so a bank is an open-pollinated project by definition, and it needs enough plants to save from - roughly twenty for a crop that pollinates itself, like beans or tomatoes, and at least eighty for one pollinated by wind or insects, like corn - or the variety narrows each generation unnoticed. Crops that cross need distance from anything they can cross with, and biennials such as carrot and beet stand in the ground two growing seasons before they set seed at all. Upkeep is annual: drying, cleaning, labelling, a germination test on each lot, and regrowing the ones that are slipping. Without that testing the failure is silent, and the cycle ends when the person running it stops.