You may be buying heirloom seeds without knowing it. If you've planted the seeds of classic vegetables such as Brandywine tomatoes or Black Beauty eggplants, you've planted heirloom seeds. These seeds boast histories dating back a century or more, long before the introduction of hybrid vegetables around World War II. Many other heirloom vegetables, especially tomato varieties, are returning to the limelight as well as part of the post-1980s movement toward sustainable agriculture.
Select your heirloom variety carefully so that it will flourish in your area, recommends the University of Florida IFAS Extension. Land-grant universities conduct tests and collect reports from growers on hybrid crops and often heirlooms as well. Read your state extension service's reports on recommended heirloom cultivars for your state. Carolyn J. Male's "100 Heirloom Tomatoes for the American Garden" advises care in picking disease-resistant heirloom tomatoes in USDA Plant Hardiness Zones 7 through 10 with their hot and humid summers.
Buy seed from a professional seed grower. Ask the grower how it defines heirloom seeds; the term "heirloom," unlike "organic," lacks an official designation. Most seed growers define an heirloom as an open-pollinated seed, created by wind and insects from similar parent plants; some define it as open-pollinated and developed before 1940.
Read the seed packet carefully, recommends Leonard Perry, extension professor at the University of Vermont. Confirm that the seeds are heirlooms and not modern hybrids. Buy seeds packed for the current year--they'll generally have the current year stamped on the back flap. Ask if the grower double-seals the package for storage between seasons.
Check if the seeds are certified organic. Seed growers receive a certificate from the U.S. Department of Agriculture if they are compliant with organic production, handling and processing.
Purchase heirloom seeds at garden centers, at organic groceries, from online specialty vendors such as Baker Creek Heirloom Seeds and Victory Seeds, from smaller regional organic seed companies, from large established national companies such as Burpee or from the Seed Savers Exchange in Iowa. Look for specific varieties of vegetables or flowers, or experiment with collections of heirloom tomato and vegetable seeds.
Buy seeds of unusual varieties in late winter or early spring; rarer cultivars may sell out.
Buy extra seeds if you plan to plant seed directly into the ground. Expect higher germination rates if you sow indoors in sterile seedling mix on a warming pad.