Heirloom tomatoes, also called heritage tomatoes in the United Kingdom, intrigue home gardeners and have even begun to make inroads into boutique produce markets, where their sales have been growing at a rate of 10 to 15 percent annually, according to Produce Business magazine. Further increases in popularity will involve educating consumers in how to use these tasty fruits in their novel colors, shapes and sizes.
Heirloom tomato seeds, unlike those of hand-pollinated hybrids crossing two pure lines, are the result of normal or "open" pollination by the wind, birds or insects within a field among similar plants. Heirloom tomatoes feature juicy, soft, flavorful, thin-skinned and sometimes lumpy-looking fruits in colors including red, pink, yellow, gold, black, purple and white.
Heirloom tomato fanciers Craig LeHoullier, a North Carolina chemist, and Carolyn Male, a New York microbiology professor, divide heirloom tomatoes into four types. Commercial heirlooms were introduced by seed companies prior to World War II and include Matchless, Redfield Beauty, Paragon and Optimus. Family heirlooms have been passed down for generations within a family; examples include Mortgage Lifter, Red Brandwine and Kellogg's Breakfast. Created heirlooms, such as Green Grape and Green Zebra, involve a cross of two heirlooms or an heirloom and a hybrid and stabilizing the desired characteristics for eight years or more. Mystery heirlooms, such as OTV (off the vine) Brandywine, result from natural cross-pollination of other heirlooms.
Penn State plant breeder William Hepler used the term "heirloom" to describe some beans friends had given him in the 1940s, according to California heirloom grower and tomato author Gary Ibsen. John Withee borrowed the term for a bean seed catalog and gave permission for Kent Whealy of Seed Savers Exchange in Decorah, Iowa, to use the term "heirloom" in 1981 a speech he gave in Tucson, Arizona.
Heirloom tomatoes offer better flavor than hybrids, both university horticulturalists and heirloom fans agree. While few are suitable for commercial shipping or chain supermarket display, home gardeners sing the praises of heirlooms, and farmer's markets and boutique grocers provide a commercial outlet for them. They also provide greater genetic diversity than hybrids, with potential for superior evolved resistance to diseases and pests.
Heirloom tomatoes, as do hybrids, range in size from grape types such as Red Pear, weighing ½ oz. according to Victory Seeds, to 2 lb. fruits produced by the Ponderosa.
As with hybrid tomatoes, heirlooms can suffer from foliage diseases. Growers can combat this with proper spacing of tomatoes in the garden to promote air circulation and copper-based sprays, writes Male in "100 Heirloom Tomatoes for the American Garden." Heirlooms with good foliage disease resistance include Cherokee Purple, Red Brandywine, Druzba and Eva Purple Ball.