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. Brown mustards is widely cultivated for its edible seed which 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 (B. nigra) but can be harvested mechanically so is more viable commercially. 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. B. juncea crispifolia. The curled or cutleaf mustards, this group has attractively curled edible leaves. B. juncea foliosa. The leaf mustards have quite large smooth-edged edible leaves. B. juncea japonica. Rather similar to B. juncea crispifolia and combined with that group by some botanists. B. juncea multiceps. The multishoot mustard group. B. juncea napiformis. A form with a swollen edible root. B. juncea rugosa. Large somewhat cabbage-like edible leaves. B. juncea strumata. A form with large edible leaf stalks. B. juncea 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.

Leaves - raw or cooked. A peppery flavor 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 flavoring. 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 flavor. The root of some forms of this species is edible. Sprouted seeds can be added to salads.

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 June to early September otherwise they may bolt. There are about 5,660 - 6,000 per 0.01 kg (1/3 oz).

Cornfields in Britain.