Lettuce is synonymous with salads as they are predominantly made from crispy green lettuce leave. Most varieties of lettuce exude small amounts of a white, milky liquid when their leaves are broken. This milk gives lettuce its slightly bitter flavour and its scientific name, Lactuca sativa derived from the Latin word for milk. Lettuce can be seasoned and served raw in green or mixed salads. The leaves are often used as a garnish. It is a cool-weather vegetable that thrives when the average daily temperature is between 60 and 70°F. It should be planted in early spring or late summer. At high temperatures, growth is stunted, the leaves may be bitter and the seedstalk forms and elongates rapidly. Some types and varieties of lettuce withstand heat better than others.

Lettuce is exceptionally low in calories and contains over 90% water. However, dark lettuce leaves are rich in folate and contain useful amounts of beta-carotene as well as vitamin C, potassium and certain phyto-chemicals that act as a mild sedative, especially when eaten with bread. Not all lettuce is created equal, but if you start your meal with a salad made of romaine lettuce you will be sure to add not only a variety of textures and flavors to your meal but an enormous amount of nutritional value.