By Elena Day
Lettuce is my favorite crop to grow and one of my favorites to eat. From October until mid-June, I generally eat lettuce at least 5 or 6 times a week. (In summer I can never get enough of tomatoes and green beans.) We always indulge the lettuce habit at the end of the main course, as in Italy. I rarely buy it from the grocery store. Since my husband constructed a hoop house we grow our own all winter. And it is possible to do so in Virginia in temperatures that fall into the teens and single digits nightly, as happened for weeks this year. (See photo from late February 2014.)
Lettuce is an annual member of Asteraceae, the aster and/or sunflower family. About 2,500 years ago, Egyptians, who initially used lettuce seeds for oil, began cultivating it for the leaves. From Egypt, lettuce spread to Greece and then Rome. The Romans named it Lactuca referring to the “lac” or milk exuded when the stem is cut.
In Egypt lettuce was a symbol of sexual prowess. It promoted love and also childbearing in women. Romans associated lettuce with male potency. The Greeks instead thought that it contributed to male impotency and female infertility. Today, we just know that lettuce is high in Vitamins A and K and potassium.
Between the 16th and 18th century numerous varieties of Lactuca sativa (sativa means “cultivated” or “sown”) were developed in Europe. In 1586 Joachim Camerarius described three types of lettuce: head lettuce, loose-leaf, and Romaine or Cos. The latter were grown in the papal gardens and also on the Greek isle of Cos during the Byzantine period. Today, lettuce is reclassified into Leaf, Romaine or Cos, Crisphead, Summercrisp (midway between Leaf and Crisphead types), Butterhead, Stem (grown mostly in Asia for the seedstalk) and Oilseed (grown for cooking oil). Crisphead is better known as Iceberg. An eighth variety—a very small amount—is used in the manufacture of tobacco-free cigarettes.
In 2010 23,620,000 metric tons (a metric ton equals 2,204 lbs) of lettuce were produced worldwide. Half the tonnage was grown in China. The U.S. grows the second largest amount, but production is less than 1/3 that of the Chinese. About 25 pounds of lettuce are consumed per person per year in the U.S.
Previous to the early 1900s, lettuce was raised and consumed close to home. With new packing, storage and shipping technologies, lettuce was soon shipped to markets further away. In the early 1900s lettuce was widely cultivated in eastern North Carolina and shipped to East Coast cities. In the 1920s, along came California visionary and owner of Fresh Express Bruce Churchill. He and his partners shipped Crisphead/Iceberg lettuce from the Salinas Valley covered in ice to cities all over the Midwest and East, as far away as Maine. As the rail cars of lettuce arrived in each town or city, people cried, “Here come the icebergs” and the name stuck, or so goes the story.
Crisphead or Iceberg lettuce has pale to white centers and contains few nutrients. It is more heat sensitive than other varieties of Lactuca sativa. It has little flavor and contains more water. By the 1940s, 95 percent of the lettuce grown in the U.S. was Iceberg. In the 1950s vacuum cooling, which allowed for field cooling and packing, advanced Iceberg production further. My husband speaks nostalgically of the wedges of Iceberg lettuce slathered with Russian dressing at family meals in his childhood. I relish finely cut Iceberg on bean tostadas even today.
In the later 1990s, with the advent of Alice Waters (Chez Panisse) and microgreens and then the bagged salad/lettuce industry, the U.S. palette rediscovered the other lettuces. However, the same agricultural model of big-is-better prevails. Currently, Romaines are grown primarily in Florida. Higher end micro-greens and salad mixes are shipped in plastic tubs from California with familiar brand names like Dole, Fresh Express, and Earthbound Farm Organic.
California’s share of lettuce production hovers around 70 percent (2007), although agribusiness production has moved into Arizona, Colorado, Texas, and even Mexico.
Genetic modification of lettuce has been ongoing since 1992. Herbicide tolerance, slower bolting in higher temperatures and resistance to insects and fungi are traits GMers seek. The lettuce/salad packing industry has seen a number of product recalls due to E. coli and Salmonella contamination in spite of washing all greens (including those labeled organic) in a weak chlorine solution.
I often find the lettuce served at higher end restaurants disappointing. If you look too closely there’s always a decomposing leaf or two in the mix. Yuck! I prefer my own and I prefer head lettuces to leaf lettuce. I germinate seeds in September and plant in October. (Optimal germination temps for lettuce hover at around 70 degrees F or slightly higher.) Seeds are germinated in the dark in the basement because it is often still too hot outdoors. I transfer seedlings to cell packs and grow these outdoors. I plant outside in rows and in the hoop house when I think they are ready and weather is appropriate; i.e. cooler. I germinate as early in January as I can, under grow lights. Depending on weather I’ll plant outside as early as mid-February.
My favorite and best performing fall/winter/lettuce is Yugoslavian Red. It’s an heirloom native to the former Yugoslavia available from Cook’s Garden and locally from Southern Exposure. With repeated freezes the outer leaves of this butterhead get crinkly, but it remains delicious. Ask Crozet resident David West, whom I convinced to grow it this year.
Apart from snails and slugs, occasional cutworms early in the spring, and the mildews in overly wet weather, lettuce is easy to grow.