Definition - What does Heirloom Seed mean?
An heirloom seed is the seed of a plant that has been carefully cultivated and passed down through many generations.
Heirloom seeds have been passed down through many generations of growers. Heirlooms are usually planted in small, isolated communities, and generally offer something of value to the grower, whether that is a unique flavor, a unique capability or tendency, or special adaptation to local growing conditions.
MaximumYield explains Heirloom Seed
Heirloom seeds can be organic, but the terms are not mutually exclusive. Heirloom seeds generally come from open-pollinated plants, and are distinct from both GMO seeds and hybrid seeds. Again, note that the term “organic” may or may not apply to these seeds, and can also apply to hybrid seeds (but not to GMO seeds).
Any heirloom seed will grow a plant that shares the characteristics of the plant’s predecessors. This is in direct contrast to the seeds of hybrid plants. Hybrids will not breed true. That is, a seed from a hybrid plant will not produce a new plant that shares the characteristics of the hybrid. It will share the characteristics of one of the two plants that were cross-pollinated to create the hybrid in the first place.
Heirloom seed can also be harvested, dried, and stored, so that one can replant the following season. This cannot be done with hybrid plants or with GMO seeds. In the case of the two latter options, the grower would need to repurchase seed each year, or buy infant plants instead. This can be quite costly.
Heirloom seed saving can help growers reduce the overall long-term costs of growing by allowing seed saving and eliminating the need to purchase new seeds or plants each year.