Vegetables - Lettuce : Introduction

Lettuce is a temperate annual or biennial plant most often grown as a leaf vegetable. In Western countries, it is typically eaten cold and raw, in salads, hamburgers, tacos, and several other dishes. In some places, including China, lettuce is typically eaten cooked and use of the stem is as important as use of the leaf.
Iceberg lettuce field in Northern Santa Barbara County
Iceberg lettuce field in Northern Santa Barbara County

A lettuce plant has a short stem initially (a rosette growth habit), but when it blooms, the stem lengthens and branches, and it produces many flower heads that look like those of dandelions, but smaller. This is called bolting. When grown to eat, lettuce is harvested before it bolts.

Lettuce is used as a food plant by the larvae of some Lepidoptera - see list of Lepidoptera which feed on Lettuces.


Vegetables - Lettuce : Varieties       

There are 5 commonly recognized types of lettuce which are ordered here by head formation and leaf structure:

    * Crisphead, also called Iceberg: lettuces form tight, dense heads that resemble cabbage. They are generally the mildest of the lettuces, valued more for their crunchy texture than for flavor. Varieties of iceberg lettuce are the most familiar lettuces in the USA. The name Iceberg comes from the way the lettuce was transported in the US in the 1930s. It was transported on trainwagons all covered in crushed ice - making it look like icebergs.

    * Summer Crisp, also called Batavian: lettuces form moderately dense heads with a crunchy texture; this type is intermediate between iceberg and looseleaf types.

    * Butterhead, also called Boston or Bibb forms loose heads; it has a buttery texture. Butterhead varieties are most popular in Europe.

    * Romaine, also called cos, is a head-forming type with elongated leaves.

    * Looseleaf: leaves are tender, delicate, and mildly flavored.

In addition:

    * Chinese lettuce types generally have long, sword-shaped, non-head-forming leaves, with a bitter and robust flavor unlike Western types, appropriate for use in stir-fried dishes and stews. Chinese lettuce varieties are divided into "stem-use" types (called celtuce in English), and "leaf-use" types such as youmaicai (Chinese: 油麦菜; Hanyu Pinyin: yóumàicài).

There are hundreds of varieties of lettuce within these categories.

Some lettuces (especially iceberg) have been specifically bred to remove the bitterness from their leaves. These lettuces have a high water content with very little nutrient value. The more bitter lettuces and the ones with pigmented leaves contain antioxidants.





source : hydroponicsearch