While people have been talking about heirloom vegetables for more than a decade, they have yet to reach an agreement on exactly what an heirloom variety is. So far, experts in the field agree that heirloom vegetables are old, open-pollinated cultivars. In addition, these varieties also have a reputation for being high quality and easy to grow. Perhaps it is best to discuss the details feature by feature.
Just how old a cultivar has to be to be an heirloom is open to discussion. Some authorities say heirloom vegetables are those introduced before 1951, when modern plant breeders introduced the first hybrids developed from inbred lines. While there are good reasons to use 1951 as a cut-off, many heirloom gardeners focus on varieties that date from the 1920s and earlier. A few, especially those re-creating World War II Victory Gardens, add introductions from the 1920s, 1930s, and the early 1940s. While some first-rate open pollinated cultivars were introduced after 1951, few gardeners include them with the heirlooms.
While many of the varieties are 100 to 150 years old, there are some heirlooms that are much older. For example, experts think certain heirlooms are actually traditional Native American crops that are pre-Columbian. Other heirlooms are old European crops, some of which have been in cultivation for almost four hundred years. Still other heirlooms trace their ancestries to Africa and Asia. They too may be much older than records indicate, but distance and language make it difficult to trace their histories.
Just as different gardeners have different ideas about how old heirlooms are, they also have different ideas about which old varieties are heirlooms. To some, nearly all the old-time varieties are heirlooms. To others, varieties can be old without being heirlooms. They exclude, for example, commercial varieties and those that appeared in the seed trade, limiting heirlooms to those local or regional varieties that were passed down from generation to generation of gardeners.
While I can appreciate the reasoning of those that view heirlooms as a narrow subset of all old varieties, I side with those who include nearly all the old-time varieties with the heirlooms for several reasons. For starters, many of the old varieties that went on to fame and fortune as commercial successes started small. Take the 'Hubbard' squash, for example. There really was a Mrs. Hubbard who found this variety, which was later popularized by seedsman James J. H. Gregory. Similarly, is the 'Brandywine' tomato, recently rediscovered by many growers, to be excluded from the ranks of heirlooms because several prominent seed companies promoted it in the 1880s?
I also consider old varieties to be heirlooms because so many of them are threatened with extinction. Should we not save such varieties just because, at one time or another, they were popular enough to be commercial successes? I am even happy to lump the old, open-pollinated varieties that still appear in seed catalogs today with the rare heirlooms. While such plants may not need preservation today, they could become orphans just as easily as their ancestors.
When heirloom gardeners refer to open-pollination, they mean that a particular cultivar can be grown from seed and will come back "true to type." In other words, the next generation will look just like its parent. For example, plant a 'Brandywine' tomato, let some of the fruit mature and collect the seed, process it properly, and store it well. The next year, plant the seed and it will grow another 'Brandywine' tomato. Seed saving is a simple enough process, and gardeners have been using it for generations.
Now, however, there are more and more vegetables that will not come back "true to type." For example, plant nearly any F-1 hybrid tomato, and go through the steps described above to save seed. The next spring, plant it, and see what happens. The seed may not even germinate, since it may be sterile. If it does sprout, the young plants will probably not have many of the characteristics that made its parent noteworthy. While hybrids have many outstanding qualities, the ability to reproduce themselves is clearly not one of them.
Heirloom gardeners are, of course, aware that the term "open- pollination" is a bit of a misnomer, because there is nothing at all open about the pollination of many heirloom vegetables. Take squash and pumpkins, for example. They cannot be left to pollinate each other willy-nilly, or the resulting offspring will be mongrels. While some may be interesting, the original type will be lost. Like the squash family, the brassicas (cabbage, cauliflower, broccoli, and their kin) also cross readily, as do several other vegetables. Gardeners who hope to save seed of such vegetables have to isolate either the plants or their flowers to prevent such unwanted crossings.
Another problem with the term "open-pollination" is that some of these crops are not even grown from seed, and no pollination, open or otherwise, is required to keep these varieties going. Potatoes, garlic, Jerusalem artichokes, and certain others are propagated vegetatively. Calling such crops "open-pollinated" feels awkward, even if such cultivars first grew from seed.
Finally, that open-pollinated varieties can come back true to type does not guarantee that they always will. Gardeners in the past knew that open-pollinated seed would occasionally produce an off-type seedling. To maintain a seed line, they looked for and rogued out off-type seedlings. Gardeners should do the same today.
What draws many gardeners to heirlooms is flavor. They want a tomato that tastes like a real tomato, not a plastic one. They long for corn that tastes like it did when they were a kid. They search for a sweet, juicy muskmelon, and wonder why cantaloupes are crisp and dry. After trying varieties that look good on the pages of seed catalogs but just don't taste like much, they turn to heirlooms.
What they find may well be something of a mixed bag. The best of the heirlooms really are wonderful. They have it all. They taste wonderful, look beautiful, and are easy to grow. No doubt about it, these varieties are terrific. There are, however, varieties that take a more experienced hand to grow well. Some are local or regional varieties that may or may not be suited to conditions in your back yard. Others are susceptible to problems unknown to earlier gardeners. Today, certain plant problems are much more common than ever before, and new, resistant cultivars may be the only ones suited to areas where certain diseases and pests are entrenched. Your local Master Gardeners or County Extension have information on plant problems in your area, and can fill you in on potential problems.
Finally, heirlooms can be quirky. Seeds may germinate slower than their modern counterparts, or they may straggle in erratically. Some may pop up after you've given up on them. As they grow, some heirlooms have traits that are downright strange. For example, I once grew an heirloom cabbage variety that seemed to tip its crown upside down until it had six or so true leaves. Then it turned right-side up and grew just fine. Other old plants will do similarly wacky things. Unfortunately, information about such traits is hard to find. About all gardeners can do is wait to see what happens, perhaps reflecting on all the things our gardening forebears knew and the wonders of biodiversity.