WOOSTER, Ohio - There's more to lettuce than what's found in your local grocery store.
From exotic, tangy varieties to small, intensely colored heads that fit in your hand, lettuces have a multitude of leaf shapes, head sizes, colors, textures and flavors to appeal to a wide range of consumers. And many types of lettuce can be grown in Ohio.
"Iceberg, red and green leaf, and romaine are the standard types of lettuce found in most stores," said Matt Kleinhenz, an Ohio State University horticulturist. "But the reality is consumers and some growers are not aware that many different kinds of lettuce are available - lettuces with unique characteristics that differ in nutritional value and that serve a range of uses."
Over the past two years, OSU researchers have studied dozens of lettuce varieties from Europe, Canada and the United States at the Muck Crops Branch in Celeryville, Ohio, and found that many are adapted to Ohio's climate and soils. The project was designed to identify varieties of field-grown lettuce that Ohio growers could produce to meet apparent increases in market demand for "specialty" types of lettuce.
"Specialty" lettuce refers to lettuces that fall into one of two major categories - heading or non-heading - but possess unique characteristics that distinguish them from the usual selection found in most stores. Examples include red-leafed or red-speckled romaines, lettuce leaves shaped like oak leaves, miniature heads the color of burgundy wine, and leaves that are green on the inside and red at the tips.
The researchers are also measuring the nutritional value of the same varieties. They hope to resume the study next year.
"People are very receptive to the idea of specialty lettuce. Currently, most of the interest originates with local or specialized markets, restaurants or growers and consumers looking for something new or unusual," said Kleinhenz. "It's important for growers to stay tuned to consumer interest. Lettuce consumption, on average, has risen over the years because of a variety of products that are offered, like the bag salad. Because of that, lettuce continues to be a major contributor to our diet. What we see evidence for now, though, is curiosity about different types of lettuce."
Lettuce is low in calories, has very little or no fat, and contains iron, calcium and vitamins. Romaine lettuce, for example, contains 20 percent of the recommended daily allowance of vitamin A. One issue the researchers are addressing is whether the nutritional value of lettuce can be managed during production. "Can growers naturally produce a healthier lettuce and will consumers reward them for it?" said Kleinhenz.
Lettuce is classified mostly by growth habit. Iceberg, romaine and butterhead are heading types, while green and red leaf lettuces do not form a head. In stem lettuce or celtuce, the stems of the plant are eaten.
"A key for Ohio growers," said Kleinhenz, "is to harness this diversity so as to satisfy the interests of not only Ohio's 12 million citizens but also consumers in other locations. One way we can help growers is to document the performance of varieties under Ohio's unique conditions. It's important to keep in mind that lettuce as a plant is sensitive to temperature, moisture and other factors and lettuce varieties are developed in places with climates very different from Ohio. We look at this research as potentially useful to growers, produce buyers, consumers and scientists."