Despite its name, Indian Lettuce probably originated in China and is currently cultivated in Malaysia, the Philippines, Indonesia, Japan, and Taiwan. Indian Lettuce is a fast-growing, upright plant that can reach 2 m (6 ft) in height. This species is a self-seeding, semi-perennial species that will self-propagate year after year once established.
The leaves and shoots of Indian Lettuce can be harvested as needed, leaving the main plant intact to continue production. Sometimes used as a folk medicine in anti-inflammatory, antibacterial, and other medications in Asia.
- Rainfall: can tolerate rainfall in excess of 3500 mm/year (140 in)
- Temperature: 25o - 30o C (77o - 95o F) it is tolerant of high temperatures and humidity as long as adequate moisture is provided. Excessive heat and/or dry conditions can produce bitter leaves. Indian Lettuce can be grown in full sun, but plants grown in partial shade will produce larger, more tender leaves.
- Soil: heavier, clay soils found in the wet tropics are suitable for growing Indian lettuce, but lighter loams are preferable.
Seed is the most common method of propagation, although cuttings are convenient in some cases. If seed is plentiful, it can be sown directly to form beds or a patch. If seed is scarce, they can be germinated in small pots and transplanted when seedlings are 3-6 cm (1-2 in) high. Although the stem is hollow, cuttings are viable as long as they are taken from mature, hardened areas of the stem. Cuttings are made 20 cm (8 in) in length and should contain at least 2-3 nodes. They are planted 10-15 cm (4-6 in) deep with at least one node above the soil. These can be either planted in pots for later transplanting or planted directly in the field.
Harvesting and Seed Production
Flowering should begin after 6-10 months, when plants are 0.8–1.0 m (2.5-3.0 ft) tall. If maximum yield is not essential, when two-thirds of the flowers are turning fluffy white the plant can be cut and put out to dry on a large sheet of paper. The first seeds to ripen are the plumpest, and most suitable for seed stock. In wet climates, seeds may have to be harvested between rains. The whole plant also can be harvested early and then hung upside down. The seeds will ripen as the thick stem continues to supply the necessary nutrients. After a complete drying, seed heads are rubbed between the hands. Three quarters of the mass you obtain will be chaff and white "feathers." Sieving with a small-gauged mesh will give reasonably clean seed. The seeds are long, flattened black ovals with pointed ends.
Pests and Diseases
No pests or diseases have been noted for this species of lettuce; furthermore Indian Lettuce appears to be highly resistant to nematodes.
Cooking and Nutrition
The younger leaves are eaten raw in salads. The stems and basal area of the older leaves contain a latex material which can be somewhat bitter. Older leaves can be steamed or boiled and eaten like spinach or cooked and used in soups, stews, stir-fries, etc. The storage life of Indian Lettuce is about one week in the refrigerator and one day in the kitchen. Indian Lettuce is a fair source of vitamins A (25,000 units/100 g edible portion) and C (25 mg/100 g).