Heirloom
A plant variety that has been passed down through generations without crossing with other varieties, typically open-pollinated and with documented history, often bred before commercial hybrid development in the mid-20th century.
Heirloom varieties are open-pollinated cultivars with documented lineage, typically developed before the widespread commercialization of hybrid seeds in the 1950s-1970s. The term has no legal definition, which means it’s used inconsistently by seed companies. A working definition: an heirloom is an open-pollinated variety that has been maintained and passed down without intentional crossbreeding, often for 50 or more years.
What Makes a Variety an Heirloom
The critical characteristic is open-pollinated stability: seeds saved from an heirloom variety produce plants identical to the parent. This is what enabled the variety’s survival over generations - farmers and gardeners could save seed and replant without purchasing new seed each year.
Many heirloom varieties have specific regional histories, family associations, or cultural significance. ‘Cherokee Purple’ tomato has documented Cherokee origin. ‘Mortgage Lifter’ was developed by a single grower in West Virginia in the 1930s and 1940s, and the name reflects his claim that selling the tomato allowed him to pay off his mortgage. ‘Dragon Tongue’ bean has Dutch origins traced to the 19th century.
Heirloom vs. Hybrid vs. Open-Pollinated
These three categories overlap in confusing ways. All heirlooms are open-pollinated, but not all open-pollinated varieties are heirlooms - new open-pollinated varieties are bred every year. Hybrids are definitionally not heirlooms because seed saved from hybrids does not produce true-to-type offspring.
See the entries on Open-Pollinated and Hybrid for complete definitions of those terms.
The Trade-offs
Where heirlooms often excel: flavor. Commercial hybrid breeding has prioritized yield, shipping durability, and visual uniformity. Flavor and texture have historically been secondary. Many heirloom tomatoes and peppers have more complex flavor than commercial hybrids for this reason.
Where heirlooms often lag: disease resistance, yield consistency, and uniformity. Modern commercial hybrids are bred with stacked resistance genes against specific soilborne diseases (tomato varieties with “VFNT” designations resist fusarium wilt, verticillium wilt, nematodes, and tobacco mosaic virus). Heirloom varieties predate most of this disease-resistance breeding and are typically more susceptible. Heirloom yields also vary more plant-to-plant and season-to-season than hybrids bred for production consistency.
Seed Saving
One practical advantage of heirlooms: you can save seed and replant. A packet of ‘Brandywine’ tomato seeds produces plants that produce ‘Brandywine’ seeds that produce more identical plants. The seed purchase is a one-time cost if you maintain the variety through annual seed saving.
For vegetable crops where seed saving is practical - tomatoes, beans, peas, lettuce, corn - heirlooms allow complete self-sufficiency in seed production. Hybrid seeds require annual purchase because hybrid seed doesn’t breed true.
Notable Heirloom Sources
Seed Savers Exchange (Decorah, Iowa) maintains the largest documented collection of heirloom vegetable varieties in the US and is the primary academic and commercial resource for heirloom seeds with verified lineage documentation.