Lettuce Classification and Suitable Weather and Soil

 

Lettuce

Lettuce Classification and Suitable Weather and Soil

Lettuce is one of the most important and oldest green salads in the world. The main homeland of lettuce is probably Iran and Turkestan. It has been cultivated and used by humans for more than 2500 years. Some writings show that in 550 BC, Iranian kings ordered its cultivation and consumption.

Some people are having the opinion that this plant is native to the Mediterranean Sea and Asia Minor, others believe that its origin is in Southern Europe, Egypt and North Africa.

From the point of view of botany, there is no known plant to which the types of lettuce can be attributed. For this reason, its origin is unknown, but its birthplace is considered to be coastal Europe or Central Asia and some in India. Lettuce was promoted in 164 AD and was very famous among the Romans. In China, the existence of lettuce has been established for five centuries.

Agricultural lettuce (2n=18) and its wild type (2n=18) have chromosomes. Both species are closely related, lettuce is fertilized by its own pollen. It is self pollinated.

Classification of lettuce

The scientific name of lettuce is lactuca sativa, which belongs to the compositae family.

Lettuce is an annual vegetable that is derived from a type of wild thorny lettuce called lactuca serriola, which is native to Asia.

Among other weeds of this genus, l.virosa and l.canadensis species can be effective in the origin of lettuce production.

According to its current existence, lettuce is divided into five types:

1.       Crisphead lettuce: This type of lettuce is strong and breaks easily.

2.       Buttarhead lettuce: This type of lettuce has a soft head and elasticity, and it is very thin tastes.

3.       Cos or romain lettuce: This type of lettuce has long and narrow leaves.

4.       Loose-leaf (bunching) lettuce: This type of lettuce has an open head.

5.       Stem lettuce: This type of lettuce has long-stemmed flowers that are edible and can be cooked.

Suitable weather

Lettuce is a cool season vegetable that grows well in areas where the temperature is between 13-16 degrees Celsius. Lettuce is sensitive to high temperatures when the temperature is high; its leaves start to burn.

The life cycle of lettuce lasts about 150 days. At the time of cultivation, two factors must be considered:

1- Temperature.

2- The length of the day.

If the lettuce is exposed to hot weather before the leaves grow enough, the production of the stem and leaves of the lettuce will have a bitter taste and will be unusable. The best areas for growing lettuce are cold and humid areas.

Soil

Lettuce can be cultivated in different types of soil. Strong soil that is drained and has a lot of organic matter gives good results. But loam soils, sandy loam soils are suitable soils for lettuce.

For a long yield of lettuce, the suitable pH of the soil is between 5.5-7. Lettuce has given a good yield in some areas in alkaline soils. For a long yield of lettuce, it needs constant moisture.