Despite being one of Japan's most popular vegetables, in the western world Komatsuna is one of the least known of all the oriental greens. Most Asian greens taste fairly similar with only subtle differences between them. Komatsuna has a lovely interesting taste: sweet, slightly sour and very tender. The mild flavour is a happy compromise between the blandness of cabbage and the sharpness of most of the oriental mustards. The common name of Mustard Spinach can be rather confusing, it is not at all pungent and has a very mild brassica flavour.
Komatsuna does not make full hearts, but matures to make lovely roundish emerald green leaves that sit atop perfectly juicy stems. This leafy green is the Japanese equivalent of our Spring Cabbage; the leaves are great in salads or simply cooked as you would spinach. Stir fry or steam as an easily prepared and very tasty and nutritious leafy vegetable.
This versatile vegetable can be used at any stage of growth from babyleaf or teen leaf stage. The leaves can be harvested individually as needed, or the whole plant can be snipped off just above the roots. The leaves will resprout from the roots after cutting and usually at least two cuttings can be made before rejuvenating the soil and replanting is necessary.
Komatsuna 'Rapido' is an improved outdoor pollinated variety. Uniform and adaptable with quick growing firm leaves. Like many other Asian greens, they are very easy to grow: vigorous and adaptable. Komatsuna are among the hardiest and most productive winter vegetables coping well with both high and low temperatures and being more tolerant of drought than most oriental brassicas. If you are looking for an all-season green that is easy to grow, tasty and nutritious, you might wish to give Komatsuna a try.
Komatsuna is usually grown in raised beds in spring through to autumn and under cover in winter. The plants are hardy to about to approx minus12°C (10°F). Although they are capable of surviving most winters outdoors, you will get better quality plants by growing Komatsuna under cover in winter, where they will continue to grow in sunny weather.
Choose an open site in full sun. Komatsuna can grow on a wide range of soil types but prefers firm rich, loamy soils with high water retention. To ensure sufficient nutrient levels, it is best to top dress or apply a liquid feed such as seaweed fertiliser during growth.
Sowing: April to September.
Seeds can be sown early in modules or sown directly into prepared soil. For seedling crop either broadcast sow or in wide drills. Mature crop sow in situ or transplant from modules space for small plants from 5cm apart up to 50cm for larger plants. Most varieties will grow 30 to 45cm (12 to 18in) tall, but growth is mostly upright so plants can be grown fairly close together if space is limited
Sow the seeds thinly 2.5cm (1in) deep and about 2 to 5cm (1 to 2in) apart. Sow seeds successionally through to September.
Keep the soil consistently moist, especially in dry periods. After one to two weeks plants are ready to be thinned out. The thinnings should be replanted.
The spacing of your final plants will vary due to the final size required. Komatsuna are usually thinned to around 25cm (10in) between plants, but the spacing can be as little as 5cm (2in) for harvesting when very young at ‘micro-veg’ stage or can be thin to 45cm (18in) apart to grow to full maturity.
Komatsuna should be watered regularly and heavily especially during dry and hot periods as the roots grow deep into the soil. Feed occasionally with a liquid fertiliser.
Harvesting: 25 days for baby leaf 55 days mature plants
Harvesting can start at any time from when the plants are 10cm (4in) high. The leaves can be cut individually as needed, or the whole plant can be harvested, snipped off just above the roots. If you cut them about 2.5cm (1in) above ground level the plants will re-shoot from the roots to produce further crops and usually at least two, sometimes three cuttings can be made over several months before rejuvenating the soil and replanting is necessary.
Komatsuna leaves can be cooked by all the methods usually used for Asian greens: steaming, stir-frying, boiling in a small amount of water, or left roughly chopped in the bottom of a soup bowl. In Japan, leaves are also pickled and the baby leaves and flowers eaten raw in salads.
In Japan, leaves are also pickled and the baby leaves and flowers eaten raw in salads. Whatever steaming brew is on the menu for the evening, cooks it just enough to make it even more verdant and flavourful while still maintaining some of its characteristic crunch. It is a major ingredient in the "I've-eaten-too-much-over-the-holidays" concoction called Nanakusagayu as well as other winter dishes. Late plantings are left to flower and can be turned into a version of a well-known spring dish, nanohana, or simply pickled.
As with most oriental brassicas, the mustard flavours strengthen slightly with age but cooking has the opposite effect and reduces any pungency.
Because brassicas are prone to soil infections, for example, Clubroot, it's important to use a minimum 3 year rotation plan.
The Japanese have likely grown Komatsuna since ancient times. It has been used in the western world since at least the 1930's. Modern taxonomists usually call it either Brassica rapa var. perviridis or Brassica rapa var. komatsuna. It is a variant of the same species as the common turnip. It is considered a biennial, though first year plants can bloom if stressed.
Komatsuna also known as Mustard Spinach is a Japanese green. Though not actually a true mustard, for its scientific classification is Brassica rapa var perviridis which places it only in the same family of plants.
How Komatsuna got its name:
Originally developed in Edo (Tokyo's former name), Komatsuna was formally named when a visiting shogun, Tokugawa Yoshimune (famous for planting maples and cherries in Tokyo), stopped for a meal at a temple. Loving this new vegetable he asked its name. The story goes that the monk answered that it had no name; it was just a green they grew and ate regularly. Like any shogun worth his salt, Yoshimune immediately righted the situation. Taking the name of the nearby river, Komatsu, and adding 'na' at the end, which means 'leaf' he baptised it with the moniker it still goes by today.
- Additional Information
Packet Size 1 gram Average Seed Count 400 Seeds Seed Form Natural Seeds per gram 400 seeds per gram Common Name Mustard Spinach Family Brassicaceae Genus Brassica Species rapa var. perviridis or rapa var. komatsuna Cultivar Rapido Hardiness Hardy Biennial Height 30 to 45cm (12 to 18in) Position Full sun Soil Frm rich, loamy soils with high water retention. Time to Sow April to September.