Common Name:

General Information

Indian lettuce is a perennial plant, often grown as an annual, growing about 1.2 metres tall.
This is a cultivated form of Lactuca indica with entire leaves[], it is sometimes grown for its edible leaves in Asia[, ]. It originated in China but is now cultivated in many parts of S.E. Asia[].

Known Hazards

Although no specific mention of toxicity has been seen for this species, many plants in this genus contain a narcotic principle, this is at its most concentrated when the plant begins to flower. This principle has been almost bred out of the cultivated forms of lettuce but is produced when the plant starts to go to seed[].

Botanical References

Range

E. Asia - China, Japan, India.

Habitat

Not known in a truly wild situation.

Properties

Edibility Rating
Medicinal Rating
Habit	Annual/Biennial
Height	1.00 m
Pollinators	Insects
Cultivation Status	Cultivated

Cultivation Details

A plant of the moist tropics, where it can be grown at elevations up to 2,000 metres. It grows best in areas where annual daytime temperatures are within the range 22 - 34°c, but can tolerate 10 - 40°c[]. It prefers a mean annual rainfall in the range 1,500 - 2,500mm, but tolerates 1,000 - 3,000mm[]. We do not know how hardy this plant will be in cooler parts of the temperate zone, though it can be grown there as an annual. It takes about 60 days from seed sowing until the first leaves are harvested[].
Grows best in a sunny position[]. Prefers a light sandy loam, but succeeds in a wide range of well-drained, fertile soils[]. Prefers a pH in the range 5 - 6, tolerating 4.5 - 6.5[].
A first harvest of leaves can be taken after 30 - 60 days, when the plants are about 50cm tall[].
Yields of the leaves may be up to 10 - 20 tonnes per hectare[].

Edible Uses

Leaves - raw or cooked[]. Added to salads or soups[].

Medicinal

The plant is digestive and tonic[].
Although we have seen no specific reports for this species, most if not all members of the genus have a milky sap that contains the substance 'lactucarium' and can probably be used as the report below details[].

The whole plant is rich in a milky sap that flows freely from any wounds. This hardens and dries when in contact with the air[]. The sap contains 'lactucarium', which is used in medicine for its anodyne, antispasmodic, digestive, diuretic, hypnotic, narcotic and sedative properties[, , , , , , ]. Lactucarium has the effects of a feeble opium, but without its tendency to cause digestive upsets[], nor is it addictive[]. It is taken internally in the treatment of insomnia, anxiety, neuroses, hyperactivity in children, dry coughs, whooping cough, rheumatic pain etc[]. Concentrations of lactucarium are low in young plants and most concentrated when the plant comes into flower[]. It is collected commercially by cutting the heads of the plants and scraping the juice into china vessels several times a day until the plant is exhausted[]. An infusion of the fresh or dried flowering plant can also be used[].
The plant should be used with caution, and never without the supervision of a skilled practitioner. Even normal doses can cause drowsiness whilst excess causes restlessness[] and overdoses can cause death through cardiac paralysis[, ].
Some physicians believe that any effects of this medicine are caused by the mind of the patient rather than by the medicine[].
The sap has also been applied externally in the treatment of warts[].

Other Uses

None known

Propagation

Seed - sow spring in situ and only just cover the seed. Germination is usually fairly quick.