A straightforward and helpful source of advice on seed saving is Garden Organic’s series of downloadable guidance leaflets, available on their website here.
What are open-pollinated plants? Why and how might you avoid cross pollination? More information can be found at www.open-pollinated-seeds.org.uk
An introduction to some of the key principles of seed saving
The basic principles of producing and saving seed vary depending on the type of plant, and these fall, broadly, into one of two groups – self pollinating and cross pollinating.
Self pollinating plants use their own pollen to pollinate their own flowers. This means that the seed that is created will be genetically the same as the parent – they will be ‘true to type’. Plants that do this include Lettuce, Peas, Beans and Tomatoes. If you are planning on saving seed from these, all you need to do is leave seeds on the plant until they are fully mature, dry and turned brown (If weather is wet you may need to pick earlier and let them dry out thoroughly indoors). When saving wet seeds such as tomato, spread them on a wooden surface or a plate rather than using paper as your seeds will stick to it and you might damage the seeds when trying to remove them. When they’re fully dry store the seeds somewhere cool, dark and dry – in a screw top glass jar in a dark cool cupboard is ideal.
Cross pollinating plants are those which rely on insects, or the wind to pollinate them. This means that pollen from another variety could cross with the plant, creating seed which is a mix of two varieties. Onions, cucumbers, sweet corn, pumpkins, squash, broccoli, beets, carrots, cabbage, cauliflower, melons, radishes, spinach, swiss chard and turnips are all cross pollinated. If you are planning on saving seeds from these, you need to take steps to prevent pollen from a different variety from pollenating the flower – this is usually done by isolating the flower in a breathable bag (e.g. a stocking) and carrying out the pollenation yourself.
You will come across the term ‘Open-pollinated’ on this website. This refers to plants that are pollinated naturally by themselves, by wind or by insects. This is in contrast to laboratory-produced hybrids (labelled F1 hybrids on seed packets) which are artificially developed, combining two varieties which would not naturally cross-pollinate in normal circumstances. These display ‘hybrid vigour’ in the first year, but plants grown from the seed they produce will revert to something other than the parent type. They are therefore not good to save or swap seeds from as you don’t know what you’ll end up producing!