LettuceLettuce is a leafy vegetable that belongs to the Asteraceae family. It is grown as an annual plant. Most of the varieties of lettuce are eaten raw or used as a base of fresh dishes such as salads. It is a rich source of various vitamins, especially vitamin K and A, but the nutritional value depends on the cultivated variety.
Lettuce can have fibrous or taproots root systems. The leaves of lettuce which have been domesticated come in a vast selection of colors, mostly in a huge selection of green hues, as well as purple and red. Some varieties with variegated varieties have also been developed. Lettuce is usually harvested prior to flowering because the flower elongates the head of the lettuce and decreases the quality of the leaves as well as their size. The vegetable also becomes bitter in flavor. The flower is usually green and produces fruits characterized by their pappus structures for wind dispersal.
This green vegetable requires ample water, especially in warmer regions, for successful cultivation. Lettuce can be also cultivated in unseasonable weather in greenhouses, specialized farms, cloches, or polyethylene covers. The most popular cultivated varieties are the leaf and butterhead types. These types however are hard to transport on a large scale, that is why they are mostly grown on truck farms or by market gardeners which are located close to the markets. The crisphead varieties have been well adapted for long-distance shipment. They are quite popular in the United States.
Lettuce is an excellent source of vitamin C, K, and A as well as various vitamins of the B group. It contains lots of important compounds and minerals such as calcium, phosphorus, magnesium, and potassium. It is low in fiber and sodium, but it is a great source of beta carotene.
The largest production of lettuce takes place in China where almost 13.5 million tonnes are produced each year. The majority of lettuce produce in China is utilized for domestic consumption. The largest exporters of this vegetable in the world are the USA and Spain. Egypt and the Mediterranean countries are other significant producers of fresh lettuce.