Helen Brownell, age 9, of Dodge City, Kan., for her question:
WHERE DO THEY GROW LETTUCE?
California leads the nation in lettuce production with about 70 percent of the country's entire commercial crop. Other top lettuce growing states include, in order of importance, Arizona, New Mexico, Colorado and Texas.
What would a green salad be without lettuce? Not very much, most people would agree.
Lettuce forms an important part in many weight control diets because it contains few calories and provides calcium, iron and vitamin A. Beside being good for you, lettuce also has a very pleasant taste.
Lettuce farming, the historians tell us, probably started in Persia as early as 550 B.C.
There are three main types of lettuce: head, leaf and romaine.
Crisp head lettuce, or iceberg lettuce, is the major type of lettuce grown commercially in the United States. Widely grown varieties of crisp head lettuce include Great Lakes and Imperial.
Butter head lettuce is a type of head lettuce but it has a more open head and has soft, oily leaves. Butter head spoils easily and so it is not as popular as crisp head. Varieties include Bibb and Boston.
Leaf lettuce forms dense, leafy clumps instead of heads. Home gardeners grow more of it than of any other kind. Popular varieties include Black Seeded Simpson and Grand Rapids.
Romaine lettuce, also called cos, grows long and upright and its leaves curl inward. The leaves are tender and can be easily damaged in shipment. For this reason, cos is the least widely grown kind of lettuce.
Most commercial lettuce grows well in temperatures between 70 and 75 degrees Fahrenheit. Some varieties have been developed for areas where the temperature is about 80.
Most commercial lettuce growers plant their crop directly in the field rather than in greenhouses.
Weeding and fertilizing of lettuce should take place at or just below the surface of the ground, or the plant's shallow root system may be injured. Lettuce also requires a steady supply of water.
When harvesting the lettuce, the workers cut off the heads just above the soil. Then they remove any dead or damaged leaves. Head and cos lettuce are harvested when the leaves are firmest, about 60 to 120 days after seeding, depending on the variety.
Leaf lettuce can be harvested whenever the leaves reach the desired size.
Lettuce spoils quickly and must be packed, cooled and shipped immediately after being cut. On most commercial lettuce farms, workers pack and cool the lettuce in the field.
Lettuce is packed in cardboard cartons and then put immediately into special refrigerated trucks. Temperature in the trucks is held just above freezing.
On some farms, the lettuce is packed between layers of crushed ice in wooden crates.