While there may be some controversy over the specifics, heirloom tomatoes are generally considered old-fashioned or “antique” varieties of the fruit. They are often produced from seeds that have been passed down from one generation to another. Available in varieties with diverse characteristics, heirloom tomatoes tend to be prized for their distinctive flavors.
Unlike hybrids, heirloom tomatoes are open pollinated. An open pollinated plant reproduces “true to type” from its own seeds. Seeds from hybrid plants, if they grow at all, typically revert to parent stock. Hybrid tomatoes are grown under carefully controlled conditions to produce qualities suitable for the rigors of commercial distribution. Because hybrids are typically picked while green and artificially ripened during shipping, they tend to be less flavorful than heirloom tomatoes.
Heirloom tomatoes are allowed to ripen naturally, so they are found only in season. Ripe heirloom tomatoes are relatively fragile and do not keep long. They can be kept at room temperature, out of direct sunlight, only a day or two. Tomatoes should not be refrigerated, as refrigeration causes both flavor and texture to deteriorate.
Varieties of heirloom tomatoes may be selected for specific characteristics of the plant. Such characteristics include the yield of fruit produced, as well as the type of fruit produced. Some heirloom tomatoes are best eaten “out of hand,” while others are superior for making juice, sauce, paste, and other products.
Appearance of mature fruit differs greatly from one variety to another in size, shape, color, texture, flavor, and other traits. Sizes range from the bite-sized cherry tomatoes to individual fruits weighing as much as two pounds (907 grams). Fruit may be oblong, elongated, pear-shaped, plum-shaped, or round, with some varieties bearing ridges on their exterior surface.
Colors include shades of white, yellow, green, pink, orange, red, purple, and black. Some varieties of heirloom tomatoes yield fruit in combinations of colors. In general, the lighter the color, the less acidic or sweeter the tomato tastes. Conversely, the deeper the color, the more acidic and definitive the tomato tastes.
Although other sorts of plants are propagated through heirloom methods, tomatoes are among the most popular. Many varieties have unique histories, and some gardeners plant heirloom tomatoes out of nostalgia or a sense of connection with the past. Others grow heirlooms because the practice helps maintain genetic diversity – a quality vital to plant survival. Regardless of motivation, a number of individuals and organizations are dedicated to securing the future existence of heirloom tomatoes.