Introduction
Lettuce belongs to family of Asteraceae. It is also called as Salad crops as it is consumed in uncooked form. Because of its diet and medicinal values, its demand is increasing rapidly. It is mostly grown for leaves purpose but sometime it is cultivated for seed and stem purpose. It is good source of Vitamin K and chlorophyll. Among different types of lettuce, loose leaf is considered as best as it contain high amount of iron and vitamin A and C. China is a top producer of Lettuce in world.
Climate
Temperature: 20-30° C Sowing Temperature: 25-30° C Harvesting Temperature: 20-28° C Rain- fall: 100-150 cm
Soil
It can grow on variety of soils but it gives good result when grown on sandy loam and silt loam soils. Also soils should be rich in nitrogen, potassium also rich in organic matter content. For good growth, ideal pH of soil should be in range of 6 to 6.8. Avoid waterlogged, acidic soils for cultivation.
Varieties
Type of Lettuce
1) Butter heads: Ready for first harvest in 45-55 days after sowing. 2) Crisp head: Ready for first harvest in 70-100 days after sowing. 3) Loose Leaves: Ready for first harvest in 45-55 days after sowing 4) Romaine: Ready for first harvest in 75-85 days after sowing.
Punjab Lettuce 1
Its leaves are crispy, shiny, light green color. It is non-heading type variety and bear loose leaves. Ready for first harvest in 45 days after sowing. Gives average yield of 35 qtl/acre of green leaves.
Other Variety
L S 1, L S 2, Iceberg, Bogampo, Great Lakes
Land Preparation
Plough land for two-three times and bring soil to fine tilth. Carry out soil testing to check nutritional status of soil. If soil is deficient in nutrients apply micro-nutrients on basis of soil test results.
Time of sowing
Prepare nursery in the month of mid-September to mid-November. Sow seeds in nursery at a distance of 15-20 cm. It takes 3-4 days for germination of seeds. After germinations, lettuce required sunlight for minimum 3-4 hours per day in morning. When seedlings become four to six weeks old, transplant them into main field.
Spacing
When seedlings are transplanted in main field, use row to row spacing of 45 cm and plant to plant distance of 30 cm.
Sowing Depth
Depth should be 2-4 cm.
Method of Sowing
For sowing of lettuce use transplanting method.
Seed Rate
To raise seedlings for 1 acre, sow 400gm seeds in 2 marla. Irrigate nursery beds at interval of week.
Fertilizer Requirement (kg/acre)
Apply well decomposed cow dung@15 ton per acre, and Nitrogen@25 kg (in form of Urea@55 kg), Phosphorus@12 kg (in form of Super Phosphate@75 kg) per acre. Apply whole amount of phosphorus and half amount of nitrogen before transplantation. Give remaining amount of nitrogen six weeks after transplantation.
Irrigation
48 hours before transplantation stop irrigating nursery beds. 30 minutes before transplantation apply good amount of irrigation. It will help in easy pulling of seedlings. Provide first irrigation, immediately after transplantation. Apply remaining irrigation, at interval of 5-6 days on light soils whereas 8 to 10 days irrigation interval for heavy soils.
Pest and their control
Aphid
If incidence of sucking pest like aphid is observed to control take spray of Imidacloprid 17.8SL@60 ml/acre using 150 ltr water
Disease and their control
Downy Mildew and Mosaic
Use resistant variety for control of downy mildew. Mosaic is seed borne disease so as a preventive measure use disease free seeds for cultivation of lettuce.
Harvesting
Loose leaf type variety is harvested when they are fully developed or reached to marketable size. Tender leaves are cut regularly with interval of one week. At the end of March or at beginning of April stop harvesting of leaves as plant attain milky stage. For seed purpose complete harvesting in May month. It gives average seed yield of 50 kg/acre.
For head type variety, carry out harvesting when heads are fully developed. Harvesting can be done by hand or by cutting of plant just above soil surface.
Carry out harvesting early in morning. It will keep leaves fresh.
Storage
After harvesting, do sorting and grading of leaves according head size, leaves size etc. After then lettuce is packed in crates or cartons. Lettuce can be stored for three weeks at temperature of 4 to 5°C at 95% relative humidity.
