History

• Lettuce has been around since ancient times and historians found evidence of its use in temple drawings. In Ancient Greece it was prescribed by doctors who believed that it would help patients sleep at night. The Romans used lettuce, as well, and it eventually moved into other modern civilizations. Christopher Columbus brought seedlings with him on his journey and shared them with those he met. It eventually grew and flourished in the modern day United States.
  
  

Identification

• When lettuce is first planted, it has a short stem that grows above the ground. This stem changes as the plant begins growing and spreads outward. The outward branches of the original stem grow green leaves on their edges, which is the part that people eat. When lettuce is left to grow free, it also grows small flowers on the petals. These flowers look like small dandelions and are typically not eaten. Modern growers harvest prior to the sprouting of the flowers.
  
  

Types

• Six of the most common types of lettuce grown and produced around the world are: Summer Crisp or Batavian is extremely crunchy and heavy. Romaine is a darker shade of green and has longer leaves, which are interrupted by a white stem running through the middle of each leaf. Looseleaf is a lighter-colored leaf, with a very mild flavor. Iceberg or Crisphead lettuce is similar to cabbage, both in terms of size, color and growing patterns. Chinese lettuce grows longer and thinner than regular lettuce, while Butterhead is lighter and softer tasting.
  
  

Identification

• Nearly every variety of lettuce grows best in mild climates where there's an equal amount of sun and rain. The plants tend to grow best in cooler climates where the soil is rich and moist. Those who grow it in different parts of the world tend to use plant food and shade to fool the plants into growing. Lettuce that's harvested for human consumption tends to fall in the 1 to 5 lb. range, though larger heads have been grown.
  
  

Geography

• Zone 6 is where the majority of lettuce is grown. The United States Department of Agriculture is credited with determining the areas. In the U.S., a number of large cities fall within the Zone 6 area, including Portland, Oregon; Chicago; Denver; and Detroit. Different varieties of lettuce are grown in different areas, though. China is the largest producer of lettuce, followed by the U.S., Spain and Italy. Lettuce is also grown in Japan, France and Mexico.