Wednesday, February 17, 2010

Heirloom Vegetables

By Nina Berryman

I sometimes forget that there is an entire vocabulary specific to farming that can sound like another language to someone not familiar with it. This is true for any topic of course, when specific, uncommon words become a regular part of everyday vocabulary. Working on an educational farm, where people are frequently being introduced to farming for the first time gives me good practice in defining agriculturally-specific words. Some vocabulary words and phrases are even specific to the Henry Got Crops! farm, such as “toro dingo-ing,” and “black plastic-ing.” For today, I’ll limit this article to the definition of an “heirloom” vegetable.

The common use of the word “heirloom” means “a family possession handed down from generation to generation.” An heirloom vegetable is actually the exact same thing. Heirloom varieties are unique varieties that have been saved for generations because of their unique, outstanding qualities of taste. In contrast, many non-heirloom vegetables on industrial farms are grown generation after generation because they store well, they ship well and they are uniform. (A plant “generation” is the same concept as a human generation- it includes all the offspring from one successful reproduction, e.g. all the eggplants that grow on one plant are part of the same generation.) The classic example is the tomato in the supermarket that looks exactly the same every day you shop, but never quite tastes as good as that funky looking, heirloom tomato at the farmer’s market.

Sometimes is easier to define something by defining what it is not. Heirloom varieties are not hybrids. A hybrid is the first generation of a cross between two different varieties (a “cross” is plant-lingo for reproduction).All the offspring from a hybrid cross will have the dominant characteristics of the two parents (say uniform size and tough skin). All the offspring of a hybrid cross are genetically very similar. These varieties are specifically bred for this desired characteristic of uniformity, so when the consumer goes into the supermarket, every tomato will look the same. The second generation will not necessarily have these characteristics and may vary greatly from the first generation. In other words, hybrids are great for predictable results in the first generation, but not for saving seed for the next generation.

Heirlooms, on the other hand are open pollinated, which means two plants from the same variety reproduce naturally by wind, insects, rain, etc. The first generation of an open pollinated cross will have more genetic diversity than that of a hybrid cross. In other words, you may have different looking tomatoes on the same plant. For instance, while all the Striped German tomatoes taste delicious, some are gigantic, some are medium sized and each one will have a different pattern of lobes and bumps and creases. However, the second generation of an open pollinated cross will vary less from its parents than the second generation of a hybrid cross. Put another way, heirlooms are a “pure” strain and if you save seed from an heirloom, assuming you do it correctly, you know what to expect from one generation to the next.

Since hybrids are very predictable in the first generation, but not at all predictable in the second generation, they are generally only grown for one season. This means that all the hybrid vegetables out there are extremely similar genetically to one another. This means they are also very vulnerable to disease and pests. One pest could wipe out all the plants of one variety. Heirlooms on the other hand are much more resilient to such outbreaks because of their genetic diversity. This is one of the main reasons we think it is important to grow heirloom vegetables.

Another reason for growing heirloom varieties is the fact that heirlooms carry a cultural significance too. Such old seeds often have fascinating stories about where they came from and who originally cultivated them. Also, because hybrids are not good for saving seed, farmers who only use hybrids become dependent on seed companies to supply them with next year’s seed. Plus, it’s more fun to grow and eat the delicious, rare, unusual looking varieties!

If you have heard of an heirloom variety, chances are it was in regard to a tomato. Heirloom tomatoes have swept the nation in popularity and some specific varieties are becoming celebrities, like the Cherokee Purple tomato. However, any vegetable can have an heirloom variety. We are growing some heirloom eggplants and dry beans for instance.

Heirloom is definitely not an easy term to define. If you are left wanting more clarification, or have further questions, here are a few suggested readings:

Any basic biology text book for further details on crosses, genetic diversity and Punnett squares (!)

“Heirloom Vegetable Gardening,” William Woys Weaver

“Growing Organic Vegetables West of the Cascades” Steve Solomon

1 comment:

  1. What a nice blog, let me say that you have what some people call: ''writer's wood'', no really,
    this could be the best thing i've ever read since that last post of ''Tabasco's Grill'' by Henry Townsend, i can't wait
    for another masterpiece of yours!!!! =)

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