How to select for best flavor:
The best way to tell a good head of iceberg lettuce is to check the butt end. It should have a creamy color and smell sweet, not bitter. As it gets older, the butt end gets browner, almost turning black. The heads should be well-formed with fresh-looking green outer leaves. Avoid hard, heavy, white heads. These are over mature and may have a large bitter core.
Peak of the season:
Iceberg lettuce is available all year in fairly steady quantity. From December through March, most of it comes from California and Arizona. As the weather heats up, the crop moves north.
Iceberg lettuce is a pretty good source of calcium, phosphorous, potassium, iron and protein. It contains fair amounts of vitamins A, C and B complex. It is also high in dietary fiber. The greener the lettuce, the higher the vitamin A content. One head contains about 70 calories, one gram of fat and about 49 mgs. of sodium.
Iceberg lettuce used to be the most popular variety in the U.S. It is still used a lot, but the more interesting flavor of leaf lettuce seems to be catching on. Iceberg lettuce is very crisp and is especially good in sandwiches or shredded.