Simple Science For Gardeners: Hybrids and Heirlooms Explained

You don't have to be a scientist (or a botanist) to be a gardener, but knowing a little bit about the science behind gardening can make digging in the dirt an even more enjoyable experience. The more you know about your plants, the more you'll appreciate them, and the better you will be able to meet their needs. In turn, your plants will give you a more beautiful and productive garden.

What Is "Heirloom"?

In the world of gardening, heirloom is a term most often used to describe certain seeds and varieties of edibles, although the term can also be applied to flowers, trees, and shrubs. Although experts disagree on exactly what constitutes an "heirloom variety," a simple way to think about it is this: heirloom seeds and vegetables are our edible heritage.Early gardeners saved seed based on the best tasting, best-performing plants in their gardens. They continued to plant, grow, save, and pass down these seeds from one generation to another--often within a family or region, which is why these varieties are called heirlooms.

Open Pollinated

Heirloom varieties promote self-pollination, or pollination of flowers by the parent plant. This means that each new generation will grow into a plant that exhibits the same characteristics as its parent (it will be a "true to type" or "true breeding" plant). For example, if you were to plant a Honey Rock melon and save some of its seed, the next year you could plant that seed and grow a Honey Rock melon identical in taste and appearance.Heirloom plants are often referred to as "open pollinated", but the term is actually a bit misleading. The true definition of open pollination is "pollination by wind or insects, not by human intervention." By definition alone, saving heirloom seeds could easily run amuck if care is not taken to avoid cross pollination within your garden. For example, if your Honey Rock melon is planted too close to a second, unrelated variety of heirloom melon, they may cross-pollinate by way of wind or insects.

In that case, seed saved from either of this year's melon varieties may no longer produce offspring like their parent plants next year. If you plant heirlooms with the intention of saving seeds, it's important to keep different varieties within the same vegetable family isolated from each other to avoid cross pollination.

A Long History

What makes an heirloom old? To be considered an heirloom, a plant variety has to have shown the same characteristics for at least 50 years, but many varieties go back much further--hundreds, even thousands of years. Although quality new heirloom varieties continue to be introduced, some authorities argue that heirloom vegetables should only include those varieties introduced before 1951, the date when modern plant breeders introduced the first hybrids.

Regardless of their age, heirloom varieties are known to reflect the flavor and appearance of the individual gardeners or regions that have worked hard to preserve them.

What Is A "Hybrid"?

A hybrid plant is the offspring of two different plant varieties or species. Two different parent plants are cross pollinated in an effort to incorporate the most desirable traits of each into the offspring. For example, plant breeders may cross two different tomato varieties, one known for its excellent flavor and the other for its resistance to disease, with the hope that the offspring will exhibit both excellent flavor and resistance to disease. Hybrids are often developed to encourage traits like bigger flowers, greater yields, disease resistance, better flavor, specific colors, earlier maturity, and winter hardiness. Seeds saved from a hybrid plant will not produce offspring "true" to its parent. Instead, the offspring may exhibit any random number of traits, including those passed down from its parent and/or "grandparents".

So Which Is Best For Your Garden?

The short answer, at least in my opinion, is both. After all, isn't a healthy garden is all about diversity? There are advantages and disadvantages to both. It's up to you to decide.

Heirloom Varieties

Advantages:

• Known for their flavor and color.
• Come in an exciting array of shapes and sizes.
• They have been carefully passed down through generations of growers and they have a heritage that is worth preserving.

Disadvantages:

• The success of some varieties is geographically specific - they may not be as hardy or disease resistant when grown out of a particular region.
• Some seeds may also be slower to germinate or germinate erratically.
• Their growth habits may not be as widely understood.

Hybrid Varieties

Advantages:

• Usually more dependable. Bred to exhibit specific traits, like disease resistance or hardiness to cold.
• They tend to be faster to germinate.
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• Their growing habits are widely understood.

Disadvantages:

• Dependability sometimes comes at the expense of other desirable traits, like flavor.
• If you find a variety you like, you are forced to buy new seeds every year, because even when self-pollinated, the offspring of hybrids will not be "true" to their parents.
• Some hybrid seeds are known to be more vigorous so may be more expensive.