Saving seed is an activity that has been performed by hundreds of generations, basically since the beginning of food production. The ability to save seed is an enormously powerful technique that lays at the very foundation of self-sufficiency.
So much can be said about saving seeds, which is actually one of four to five more common types of plant propagation. The others include root division, plant separation, cuttings, and layering. Depending on the type of plant, one or more of these propagation techniques can be employed to obtain more plants of the same species.
Saving seed preserves genetic diversity. A seed can actually be thought of as a little piece of infinity, with all possibilities capable of being expressed from within. When germination occurs, the seed actually express one of these possibilities. Some plants will yield seed that gives more plants identical to the previous generation (seed said to hold true), while other plants yield seed that can bare very little resemblance to its parent. For example, lettuce holds true while apple and orange seeds do not. The benefit of saving a cultivating seeds from plants that do not hold true are many and include the preservation of genetic diversity, increased pollination of the desired varieties, and most importantly, the possibility of discovering a new breed with more desired characteristics.
I also want to note here a problem with hybrid seeds and more importantly, with genetically modified seeds. Companies like Monsanto are actively altering the genes and expressions of common crops such as corn and potatoes. Often times, genes are tweaked to achieve herbicide resistance, drought resistance, or the exaggerated expression of a desirable trait such as size, color, or the ability to keep for long periods of time. The problem with this is that the offspring seed of these modified plants are often sterile and/or very different from the parent plant. Thus, farmers are being robbed of their naturally endowed ability to save seeds from nature and preserve, propagate, and multiply this bounty according to their liking.
Here are some pictures of me saving lettuce seed. In November, I bought an organic lettuce variety mix from Johnny´s Selected Seeds. There were about 7 types of lettuce in this mix and we sowed and planted them in December. While we did harvest numerous outer leaves as the lettuce matured, we never harvested whole heads. We instead let the heads of lettuce bolt, which means they send up a stalk from the middle, which bears flowers and then seed. Once the plant dies off and the stalk turns brown, the flowers should be gone and the seedpods should be well formed and filled with developed seeds. Do not worry about whether the seeds are still wet, but dry days re preferable for collecting seed.
I cut the plant and then I use newspaper and a fine mesh screen. I basically crumble all the seedpods over the newspaper and then run them through the screen several times. This is known as threshing, in which you are removing the covering from the actual lettuce seed. Please note that the screening process should be relatively light, as the seeds will break if they are handled too roughly.
Once they have been screened several times, I leave the on newspaper in a dry and airy spot for several days to dry. Each day I move them around to help them dry more quickly. After a few days of drying, they can be stored in glass jars for at least one year and often up to 3 or 4 years.
So basically, I bought the lettuce mix, which gave me several varieties of lettuce. Now, with my seed saving activity, I never again have to buy lettuce seed for as long as I live. I could even pass this same seed down to future generations and for years, the same organic lettuce can be preserved and grown in the garden, without ever having to purchase new seed.