Curcuma longa is an erect, strongly tillering, herbaceous, perennial plant growing about 1 metre tall from an underground rhizome. It has a short stem and 6 - 10 tufted leaves about 30 - 50cm long.

Turmeric is a very common dye plant and is also one of the most common flavourings used in Asian cuisine.
It is believed to have been first domesticated in South or Southeast Asia and is now widely cultivated in tropical and subtropical regions for its use as a spice, dye plant, medicinal plant etc.

Known Hazards

If the roots are cut the yellow colour will stain fingers or cloth indelibly, and contact may cause an allergic skin reaction in some people.

Habitat

Not known in a truly wild state, though it appears naturalized in some areas, such as the teak forests of east Java.

Cultivation Status

Cultivated

Cultivation Details

Turmeric is a plant of the moist tropics and subtropics, where it is found at elevations up to 2,000 metres. It grows best in areas where annual daytime temperatures are within the range 20 - 28°c, but can tolerate 18 - 32°c.
It prefers a mean annual rainfall in the range 1,000 - 2,000mm, but tolerates 800 - 3,000mm.
Prefers a fertile, well-drained soil in a shaded position.
Succeeds in full sun and in light shade.
Prefers a pH in the range 6 - 7, tolerating 5.5 - 7.5.
In India the crop is planted just before the rainy season. The leaves appear above ground in about 30 days, and the crop is harvested when the leaves wither after 270 - 365 days.
Yields of fresh raw turmeric usually vary between 7 - 9 tonnes per hectare when turmeric is grown as a rain-fed crop, and between 17 - 25 tonnes when it is grown under irrigation.
Yields up to 50 tonnes have been obtained.
The yield of the dried spice varies between 400 - 1,700 kilos/ha.
Plants are adapted to growing in areas of seasonal drought in monsoonal forests.

Edible Uses

The rhizomes are dried and ground into a yellow powder.
This is used as a yellow colouring agent and flavouring in a wide range of foods such as rice, curries, piccalilli, gravies and sauces.
It is an essential ingredient of curry powders.
The plant has primary, ovate or pear shaped rhizomes that are 5 - 8cm long and 1 - 5cm wide. Growing from these are secondary, finger shaped rhizomes, with an inner yellow colour, a characteristic odour and a slightly bitter taste.
The young shoots and rhizome tips can be eaten raw or cooked.
They can be chopped finely and added to curries etc, where they impart a subtle, spicy flavour.

Medicinal

The rhizome is a pungent, bitter, astringent herb that stimulates the digestive, respiratory and circulatory systems and uterus, normalizes energy flow and has antiinflammatory and antibiotic effects. It has also been shown to lower blood-cholesterol levels and inhibit blood clotting.
It is taken internally in the treatment of a wide range of disorders including digestive and skin complaints, gastric and duodenal ulcers, poor circulation, uterine tumours, jaundice, liver disease, menstrual problems, rheumatism, and to relieve cough and tuberculosis.
Externally, the rhizome is used to treat a range of skin conditions including itch, insect bites, small injuries, sores and ringworm.
The powdered rhizome is used in a treatment for sores and rashes in infants. Indo-Fijians apply a poultice of the rhizome to sprains and bruises. A solution is used to treat eye diseases and open wounds. The rhizome is pounded and squeezed in water to prepare a solution to treat fish poisoning and to treat purulent conjunctivitis.
The leaves are applied to bruises and painful skin.
Juice from the leaves is used to treat aching eyes.
Colds and runny noses are treated by inhaling the vapour from the crushed leaves.

Agroforestry Uses

None Recorded

Other Uses

The root is a source of yellow and orange dyes for silk and wool.
Most notably, it is used for colouring the robes of Buddhist monks.
Turmeric is recognized in the dyeing industry as one of the 'direct colours', capable of dyeing cotton without a mordant. However, as the pigment is extremely sensitive to light, it easily discolours, and when applied to cotton, wool or silk it is usually used in a weak solution of acetic acid or alum. Alkali in the dye bath can be used to impart a reddish hue.
The rhizomes are also used in as a cosmetic for the body and face.
The dye can be used as an indicator of acids and alkalis.
The cured and dried rhizomes produce an aromatic yellow-orange powder that is used for the preparation of solvent-extracted oleoresin.
The root has insecticidal, fungicidal and nematicidal properties which make it a potential biocide.

Propagation

Seed - best sown as soon as it is ripe.
Germinates best at temperatures around 20°c.
Division of the rhizome when the plant is dormant.