Testing seeds for germination
There are tables setting out the viability of seeds, but these will not necessarily apply to home-saved seed because ripeness and drying may well be faulty. If you look at a seed packet you should see printed there the legal germination percentage: this varies from 90 % for beans down to as low as 25% for.
Test your seeds by cutting two round pieces of blotting paper and fitting them inside saucers, damping the paper, and setting out between 20 and 100 seeds on each. Place a second saucer on top of each and put them inside an airing cupboard or any other place that will be at a temperature of 20-27°C (68-80°F) for three weeks. Then bring them out, remove the covering saucer, and count how many seeds have sprouted. If your percentage is lower than the one on the seed packet, sow rather more to avoid wasting garden space.
Seed-testing time should start at the end of mid-winter or the beginning of late winter.
If you want your seed to last, do not store it on a damp shelf in the garden shed, but in a dry sealed envelope or tin in a cool place—a cool room in the house will do, as long as it is dry. To make sure that it keeps dry, you can add a little anhydrous calcium chloride, silica gel or a few grains of rice to the seed in the container, and seal the latter with vaseline.
Seeds of different vegetables can be kept for different lengths of time. Remember, it is legal to give seed to a friend or relative, but not to sell it or even advertise it in exchange for other goods.