In agriculture and gardening, seed saving is the practice of saving seeds or other reproductive material (e.g. tubers) from open-pollinated vegetables, grain, herbs, and flowers for use from year to year for annuals and nuts, tree fruits, and berries for perennials and trees. This is the traditional way farms and gardens were maintained. In recent decades, there has been a major shift to purchasing seed annually from commercial seed suppliers, and to hybridized or cloned plants that do not produce seed that remains "true to type"-retaining the parent's characteristics- from seed. Much of the grassroots seed-saving activity today is the work of home gardeners. However, it is gaining popularity among organic farmers, permaculturists and enthusiasts with cultural or environmentalist interests.
Open pollination is the key to seed saving. Plants that reproduce through natural means tend to adapt to local conditions over time, and evolve as reliable performers, particularly in their localities, known as landraces or "folk varieties". The modern trend to rely on hybridized and cloned plants negates these evolutionary processes. Hybrid plants are artificially cross-pollinated, and bred to favor desirable characteristics, like higher yield (in monocultures) and more uniform size to accommodate mechanized harvesting. However, the seed produced by the second generation (F2) of the hybrid does not reliably produce a true copy of that hybrid (it 'segregates') and often loses much of its yield potential. Likewise the cloned cultivars of many perennials such as seedless grapes have lost the ability to even reproduce by seeds.
While comprehensive figures are hard to come by, one popular view today holds that thousands of varieties of vegetables and flowers are being lost, due to reliance on commercial hybrid seed. Widespread use of a relatively few mass-marketed hybrid seed varieties, in both home gardening and commercial farming, is said to be eliminating many open-pollinated varieties, especially the local variations that were naturally developed, when local seed-saving was the common practice. The concern is that this erodes the gene pool, resulting at some point in less hardy, more vulnerable plants. Countering this trend (an environmental and sustainability issue), and an affinity for variety and tradition, are the principal motivations for many large seed-saving groups.
To be successful at seed saving, new skills need to be developed that enhance the capacity of growers to ensure that desired characteristics are retained in their landraces: learning the minimum number of plants to be grown which will preserve inherent genetic diversity, recognizing the preferred characteristics of the cultivar being grown so that plants that are not breeding true are selected against, understanding and promoting the breeding of improvements to the cultivar, using seed storage methods that maintain viability, learning the conditions that maximize germination, and detecting the presence of diseases that are seed-borne so that they can be eliminated.
Care must be taken, as training materials regarding seed production, cleaning, storage, and maintenance often focus on making landraces more uniform, distinct and stable (usually for commercial application) which can result in the loss of valuable adaptive traits unique to local varieites (Jarvis et al., 2000).
Additionally, there is a matter of localized nature to be considered. In the upper northern hemisphere, and lower southern, one sees a seasonal change in terms of a cooler winter. Many plants go-to-seed and then go dormant. These seeds must hibernate until their respective spring season.
However, in the tropics, such as Puerto Rico or nearer the equator, tropical fruits and plants reign. In this case, one eating a local fruit must exercise caution in tossing a seed out an open window after eating the flesh as it may sprout. These seeds having a great, if rather temporary, vitality, with no dormant period, and a viability of mere hours at best in most cases once the flesh of the fruit is removed.
To successfully save seed, understanding and mimicking nature of the plant seed in question, is the direction in which to go. Cold areas experience the dehumidifying aspects of winter, just as chapped hands and lips do, as well as cold. This is not seen in the tropics.