Lettuce (Lactuca saliva) has a long history of use. Lettuce (Oilseed variety) was first cultivated for its seeds from which oil was extracted.
At some point, the milky sap in the plant was bred out, making leaves less bitter. This made possible selections that were grown for their leaves. There are depictions of a romaine-type lettuce on the temple wall of a pharaoh. It is believed that Christopher Columbus’ second voyage to America brought lettuce to these shores.
Colonial American gardens grew some 15 varieties of lettuce. Two of these, Capuchin (now called Tennis Ball) and Aleppo are still available today. A variety called Brown Dutch, whose leaves are tinged a reddish-brown color, is listed in Thomas Jefferson’s notes as being grown in Monticello. It is available today as well.
The B.K. Bliss and Sons catalog of 1873 listed four varieties of lettuce while the W. Atlee Burpee Annual Catalog of 1886 listed 36 varieties. Today’s gardeners can still purchase other heirloom varieties such as Amish Deer Tongue, Oakleaf and Rouge d’Hiver (Red Winter). Modern seed catalogs may list as many as 75 varieties of lettuce. You can avail yourself of slow-bolting, heat tolerant, cold hardy, mini versions and even celtuce (stem lettuce). To further add to the possibilities, lettuce seeds are available for hydroponic growing, pelleted types (seeds coated with a clay, lime and perlite mixture or similar, to make them easier to handle) and red or bronze-leaved sorts.
Lettuce is classified into types based on plant characteristics. The afore mentioned Oilseed is still grown in Egypt for its larger seeds. The leaf types of lettuce don’t form a head and are often harvested when young.
Crisphead lettuces, like Iceberg, form tight cabbage-like heads. Butterhead types form loose heads and are exemplified by Boston lettuce. Romaine or cos lettuce forms elongated leaves into an upright head. The stem lettuce (also called asparagus or Chinese) grows to 18-24 inches high, produces some leaves and is harvested when its stem is a half-inch thick. Since it is heat tolerant, leaves can be harvested early and stems later. This lettuce is used in Chinese cooking and can be eaten raw or cooked.
Lettuce is easy to grow in the garden or in containers which is why it is such a popular vegetable with gardeners. Because lettuce seeds have a thermal dormancy, they won’t germinate when soil temperatures get above 68 degrees. So, grow lettuce in spring or fall. Seeds generally take 2 to 15 days to germinate. Leaf type lettuces can be harvested in about 30 to 40 days, romaine in 43 to 58 days and crisphead in 70 to 80 days. Provide shade to extend the growing season into summer for spring-planted lettuce or try one of the heat tolerant varieties.
The darker green the leaves, the more nutrients they contain. Red-leaf types provide antioxidants. Fresh lettuce keeps for 2 to 3 weeks if stored properly. I harvest lettuce when the leaves are dry, and place them into a plastic container and then in the refrigerator. Layering leaves between sheets of paper towels is sometimes helpful. Any water droplets or condensation that adheres to the leaves will cause decay. So, it is better to wash lettuce just before use. Lettuce can be used in salads, soup or stir fries. Boston and romaine types work well for wraps.
Black-seeded Simpson is on my list for this year. It will regrow when cut and is heat tolerant. If lettuce is on your vegetable growing list, why not try something different this year? Maybe a red leaf romaine is just the thing!