Chinese mustard (*Brassica juncea*) is an annual herb that will grow from 30 to 46 cm tall. It can be invasive in some areas, but it’s favored for its edible qualities in other locations. The leaves and flowers are edible and have a hot mustard taste. Young leaves are flavorful in salads, while older leaves are best as cooked greens. Seeds are harvested from summer to fall and provide a spicy mustard flavor to dishes.
I. Appearance and Characteristics
Brassica juncea, commonly brown mustard, Chinese mustard, Indian mustard, leaf mustard, Oriental mustard and vegetable mustard, is a species of mustard plant.
Mustard greens are a cool season vegetable, grown for their peppery edible leaves. You can eat young mustard green leaves raw in salads for a spicy kick or cook older leaves into soups, stews and stir fries for added flavour.
Mustard greens are frost tolerant and fast growing – they’ll be ready to start picking leaves from just 5-6 weeks after planting, making them the perfect crop to grow amongst longer term brassicas like broccoli, cauliflower and cabbage.
II. How to Grow and Care
Sunlight
Like most plants, chinese mustard must be spaced adequately to ensure each plant receives enough sunlight on all above ground plant plants and to ensure that disease is unable to take hold. The majority of Brassicaceae will thrive in around 6 hours of direct sunlight each day. The plants should be positioned in full sun though care should be taken to ensure that they are protected from wind.
Watering
Chinese mustard requires plenty of water to develop and grow. When propagating, potted seedlings should be stood in water to ensure that compost is sufficiently moist before planting to ensure that roots establish quickly. Once planted, surrounding soil should be watered well, and watered regularly whilst the plants establish themselves and throughout their growth.
Soil
Chinese mustard grows best in firm, fertile and naturally-draining soils. Areas to be planted should be dug over in the preceding fall, with stones removed and well-decomposed manure or compost worked in ready for the growing season. Growers can also tread on the soil area to ensure that air pockets have been removed and the surface made adequately firm. In terms of pH, all families of Brassica grow best in soils just below neutral at 6-7 except for collards and mustards which enjoy slightly more acidic soils and cabbages that will tolerate slightly alkaline soils up to a pH of 7.5.
Fertilizing
Due to their large, dense leaves most brassicas have high nutrient demands relative to other vegetable crops. It is important that these nutritional needs are met if plants are to reach their full potential. Serious growers will buy soil testing kits to find out how rich or poor a soil is in the key macronutrients nitrogen, phosphorus and potassium.
The main nutrient demand is nitrogen which in absolute application terms should be about four times that of the other two macronutrients. The best approach is to apply manure or compost in the fall for supplying nitrogen, along with some general purpose fertilizer in the spring to replace the nitrogen lost during winter rain. General purpose fertilizer such as fish, blood and bone can be used.
Fertilizer can be applied, broadcast or banded for chinese mustard. The method used and the fertilizer chosen to supply nutrients to brassica crops varies hugely depending on location, the family being planted and climate. However, using a lime-containing fertilizer such as calcium ammonium nitrate helps to hold up soil pH which is preferential to many brassicas. Banding can be used in place of broadcast spreading however it is advisable to trial quantities applied to prevent overfeeding.
Planting Instructions
Propagation of chinese mustard seedlings is best started indoors with seeds planted six to four weeks before the last frost in spring or, for a winter crop ten to twelve weeks before the first frost in the fall. The seeds should be sown to a depth of a 1.3 cm. Once germinated, seedlings can be thinned to 8 cm between each plant. They can be transplanted once a height of 6 cm has been reached; for Brussels sprouts and kale, the height should be about double this. Spacing then depends on Brassicaceae but ranges from 30 to 76 cm.
Pruning
The large, thick low-lying leaves characteristic of many brassicas call for fairly regular maintenance and occasional pruning to ensure that leaves touching the ground do not start to rot. As well as removing possible sites for diseases to take hold, it helps to ensure that the plant’s energy is directed towards healthier growth. Any yellow, flat-looking leaves can simply be torn off or pruned with scissors. Large, healthy leaves covering other plants can also be removed but should be eaten.
III. Uses and Benefits
- Culinary uses
The leaves, seeds, and stems of this mustard variety are edible. The plant appears in some form in African, Bangladeshi, Chinese, Filipino, Tripuri, Italian, Indian, Japanese, Okinawan, Nepali, Pakistani, Korean, Southern and African-American (soul food) cuisines. Cultivars of B. juncea are grown for their greens, and for the production of mustard oil. The mustard condiment made from the seeds of the B. juncea is called brown mustard and is considered to be spicier than yellow mustard.
Because it may contain erucic acid, a potential toxin, mustard oil is restricted from import as a vegetable oil into the United States. Essential oil of mustard, however, is generally recognized as safe by the U.S. Food and Drug Administration. In Russia, this is the main species grown for the production of mustard oil. It is widely used in canning, baking and margarine production in Russia, and the majority of Russian table mustard is also made from B. juncea.
The leaves are used in African cooking, and all plant parts are used in Nepali cuisine, particularly in the mountain regions of Nepal, as well as in the Punjabi cuisine in the northern part of the Indian subcontinent, where a dish called sarson da saag (mustard greens) is prepared. B. juncea subsp. tatsai, which has a particularly thick stem, is used to make the Nepali pickle called achar, and the Chinese pickle zha cai. This plant is called “lai xaak” in Assamese and it is cultivated hugely during the winters. It is eaten in any form in Assam and Northeast, be it boiled or added raw in salad, cooked alone or with pork.
The Gorkhas of the Indian states of Darjeeling, West Bengal and Sikkim as well as Nepal prepare pork with mustard greens (also called rayo in Nepali). It is usually eaten with relish and steamed rice, but can also be eaten with roti (griddle breads). In Nepal it is also a common practice to cook these greens with meat of all sorts, especially goat meat; which is normally prepared in a pressure cooker with minimal use of spices to focus on the flavor of the greens and dry chillies. B. juncea (especially the seeds) is more pungent than greens from the closely related B. oleracea (kale, broccoli, and collard greens), and is frequently mixed with these milder greens in a dish of “mixed greens”.
Chinese and Japanese cuisines also make use of mustard greens. In Japanese cuisine, it is known as takana and often pickled for use as filling in onigiri or as a condiment. Many varieties of B. juncea cultivars are used, including zha cai, mizuna, takana (var. integrifolia), juk gai choy, and xuelihong. Asian mustard greens are most often stir-fried or pickled. (See pickled mustard.) A Southeast Asian dish called asam gai choy or kiam chai boey is often made with leftovers from a large meal. It involves stewing mustard greens with tamarind, dried chillies and leftover meat on the bone. Brassica juncea is also known as gai choi, siu gai choi, xaio jie cai, baby mustard, Chinese leaf mustard or mostaza.
- Green manure
Vegetable growers sometimes grow mustard as a green manure. Its main purpose is to act as a mulch, covering the soil to suppress weeds between crops. If grown as a green manure, the mustard plants are cut down at the base when sufficiently grown, and left to wither on the surface, continuing to act as a mulch until the next crop is due for sowing, when the mustard is dug in. In the UK, mustard sown in summer and autumn is cut down starting in October. April showings can be cut down in June, keeping the ground clear for summer-sown crops. One of the disadvantages of using mustard as a green manure is its propensity to harbor club root.
- Phytoremediation
This mustard plant is used in phytoremediation to remove heavy metals, such as lead, from the soil in hazardous waste sites because it has a higher tolerance for these substances and stores the heavy metals in its cells. In particular, Brassica juncea was particularly effective at removing cadmium from soil. The process of removing heavy metals ends when the plant is harvested and properly discarded. Phytoremediation has been shown to be cheaper and easier than traditional methods for heavy metal reduction in soils. In addition, it has the effect of reducing soil erosion, reducing cross-site contamination.
IV. Harvesting and Storage
Harvesting of brassicas depends on family and variety. Summer cabbages cauliflower kohl and common broccoli can all be harvested from the end of summer whilst many others are good for picking in the fall or winter. Low growing brassicas such as cabbages should be harvested by cutting close to the ground level using a sharp knife. When harvesting cabbages the whole plant should be lifted to reduce the risk of club root. Broccoli should be harvested when flower shoots are well formed. Kale on the other hand can be harvested throughout the season on a frequent basis.
