This species has been cultivated as a food crop for many hundreds of years and, in that time, several quite distinct forms have arisen. The nomenclature of these forms is confused, to say the least, and by no means universally accepted. We have followed the treatment used by GRIN, though it is very likely to be revised in the future[].

Common Name: Brown Mustard

General Information

Brassica juncea is an erect, often unbranched annual to biennial plant growing up to 160cm tall when in flower[]. It is the parent of several distinct forms that are grown for food, oil etc - these are described in separate records.
Brown mustard is widely cultivated for its edible seed which is a source of oil; is used to make the condiment 'brown mustard'; and is also sprouted as the mustard of mustard and cress[, ]. It has only 70% of the pungency of black mustard (Brassica nigra) but can be harvested mechanically so is more viable commercially[]. In addition to its edible uses, the plant also has a range of medicinal uses, is grown as a green manure and can be used to remove heavy metals from the soil.
The plant has escaped from cultivation in many areas and can become an invasive weed[].

Known Hazards

An oil obtained from the seeds can have a high content of erucic acid. There have been some health concerns over the consumption of high levels of erucic acid n humans, though this is still controversial. At present (2012), several countries only allow cultivars with low erucic acid levels to be used for food.

Botanical References

Range

Probably originating from the central Asian Himalayas to China, though it has been cultivated for so long that it is not known truly wild

Habitat

Cornfields in Britain[].

Properties

Weed Potential	Yes
Edibility Rating
Medicinal Rating
Other Uses Rating
Habit	Annual
Height	0.30 m
Growth Rate	Fast
Pollinators	Bees
Self-fertile	Yes
Cultivation Status	Cultivated, Wild

Cultivation Details

Originating from the central Asian Himalayas to China, Brassica juncea has long been cultivated and many forms have been developed (see separate records). Plants can be grown in the tropical lowlands as well as in much cooler conditions[]. The plant is reported to tolerate a temperature range of 6 - 37°c and an annual precipitation of 500 - 4,000mm[].
Succeeds in full sun in most well-drained moisture-retentive fertile soils[, , ]. Prefers a heavy soil and some shade[]. Dislikes very hot weather[]. Plants tolerate high rainfall and, although fairly deep rooted, are not very drought resistant[]. Tolerates a pH in the range 4.3 to 8.3.
This species is one of four species used to produce mustard.[] The other three (see their individual records for more information) are:-
Brassica carinata. Ethiopian mustard. This is scarcely used outside of the highlands of Kenya and Ethiopia.
Brassica nigra. Black mustard is only suitable for hand-harvesting and is rapidly losing importance as a commercial crop.
Sinapis alba. White mustard. The major mustard in cultivation, accounting for almost 60% of the market.
This species has also been cultivated in the Orient for many hundreds of years and a wide diversity of forms has been developed with edible leaves, stems, roots and seeds. These forms have been classified by the botanists as follows and separate entries have been made for each of them.
Brassica juncea integrifolia crispifolia. The curled or cutleaf mustards, this group has attractively curled edible leaves.
Brassica juncea integrifolia rugosa. Large somewhat cabbage-like edible leaves.
Brassica juncea integrifolia strumata. A form with large edible leaf stalks.
Brassica juncea integrifolia subintegrifolia. The leaf mustards have quite large smooth-edged edible leaves.
Brassica juncea japonica. Rather similar to Brassica juncea crispifolia and combined with that group by some botanists.
Brassica juncea napiformis. A form with a swollen edible root.
Brassica juncea tsatsai multiceps. The multishoot mustard group.
Brassica juncea tsatsai tumida. A form with swollen edible stems.
Plants take from 2 - 5 months from sowing to maturity, depending on the season and the cultivar[]. They prefer a fairly high stable temperature and are well adapted to short day length[]. Many are best grown in warmer climates than Britain but there are several cultivars that grow well in this country[].
Plants have a rooting depth of between 90 - 120 cm[].
A good bee plant[].

Edible Uses

Leaves - raw or cooked[, , , , ]. A peppery flavour that can range from mild to hot, this is one of the most highly prized cooked vegetables in the Orient[]. The leaves can also be eaten raw, when finely shredded they make a very acceptable addition to mixed salads[]. The protein extracted from the leaves mixes well with banana pulp and is well adapted as a pie filling[].

Flowers and young flowering stems - raw or cooked[]. Sweet and succulent[].

An edible semi-drying oil is obtained from the seed[, , , , ]. The seed contains 25 - 30% oil[].

The seed is used as a mustard flavouring[]. It is the source of 'brown mustard'[], a prepared mustard that is milder than that produced from other species[]. Pungency of mustard develops when cold water is added to the ground-up seed - an enzyme (myrosin) acts on a glycoside (sinigrin) to produce a sulphur compound. The reaction takes 10 - 15 minutes. Mixing with hot water or vinegar, or adding salt, inhibits the enzyme and produces a mild bitter mustard[]. Black mustard comes from B. nigra and white mustard from Sinapis alba.

The seed is also used whole in curries and pickles[]. They are often heated in oil to destroy their pungency and give them a nutty flavour[].

The root of some forms of this species is edible[].

Sprouted seeds can be added to salads.

Medicinal

Although not usually used medicinally, the seed is a warming stimulant herb with antibiotic effects[].
Reported to be anodyne, aperitif, diuretic, emetic, rubefacient, and stimulant, Brown Mustard is a folk remedy for arthritis, foot ache, lumbago, and rheumatism[].

The seed is used in the treatment of tumours in China[]. In Korea, the seeds are used in the treatment of abscesses, colds, lumbago, rheumatism, and stomach disorders[].

The root is used as a galactagogue in Africa[].
Ingestion may impart a body odour repellent to mosquitoes[].

Mustard oil is used in the treatment of skin eruptions and ulcers[]. Believed to be aperient and tonic, the volatile oil is used as a counterirritant and stimulant[].

In Java the plant is used as an antisyphilitic emmenagogue[].

Leaves applied to the forehead are said to relieve headache[].
The Chinese eat the leaves in soups for bladder, inflammation or haemorrhage[].

Agroforestry Uses:

There is some evidence that if this plant is grown as a green manure it is effective in reducing soil-borne root rots in pea crops[]. This is attributed to chemicals that are given off as the plants decay[].
Brassica juncea has been found to have a high potential to remediate cadmium, lead and zinc from polluted environments. It is especially effective with lead, which it concentrates in the roots and greatly restricts its translocation to the shoots. This plant can therefore be grown in environments that are contaminated with heavy metals, after which the plant biomass can be harvested and burned to ash to recover the metals or to be disposed of appropriately and safely[].
The plant can be used as bioremediator to reduce boron and selenium levels in contaminated soils[].

Other Uses

An oil is obtained from the seed[]. It can be used as hair oil and as lubricant. The oil of cultivars bred for extra high erucic acid content is used for industrial purposes[]. A peculiar use of mustard oil is to retard the fermentation process when making cider from apples[].

Propagation

Seed - sow in situ from early spring to early autumn in order to obtain a succession of edible leaves. Most varieties of Oriental vegetables belonging to this species are best sown from late early summer to early September otherwise they may bolt[].
There are about 5,660 - 6,000 per 0.01 kg (1/3 oz)[].