Mizuna: planting, harvest and uses


As a horticulture student I mainly studied crops and cultivation techniques. It fascinates me how many diverse plants can grow from small, nearly identical seeds.

Favourite fruit: blueberries, grapes, raspberries, pears
Favourite vegetables: mushrooms, peppers, kohlrabi, onions, garlic

At first glance, you might mistake mizuna for the more common rocket, but the differences become more apparent upon closer inspection. Mizuna’s flavour is particularly distinctive.

green feathery mizuna leaves
Mizuna is a leafy vegetable that has already been to space on the ISS [Photo: ElenVik/ Shutterstock.com]

While mizuna (Brassica rapa subsp. nipposinica) is relatively new in the UK, the leafy vegetable is very popular in Japan. Mizuna has been gaining more attention and was even grown in space aboard the ISS in 2019. Read on to find out how to grow mizuna in your garden.

Mizuna: origin and description

Also known as kyona, potherb mustard or Japanese mustard greens, the fast-growing leafy brassica originates from Asia, where it has long since been cultivated.

Mizuna is an annual plant that grows in a dense rosette, producing high yields. Depending on the variety, mizuna leaves come in shades of green, red and purple and have toothed edges and a slender white stalk.

green and red mizuna
Whether green or red, mizuna leaves are distinctively serrated [Photo: BearFotos/ Shutterstock.com]

When temperatures rise and if there is a lack of water, mizuna can bolt prematurely in late spring, showing off small clusters of yellow flowers on long stalks. Mizuna flowers have four petals as is typical for the Brassicaceae family. They grow in a cross shape and smell a bit like mustard and honey.

Mizuna grows around 20 to 30cm tall and its flowers have a medium nectar and pollen value. They are particularly popular with wild bees and butterflies. The flowers turn into about 5cm long seed pods, in which the round, brown mizuna seeds ripen.

yellow mizuna flowers on slender stalks
Mizuna flowers are quite small and inconspicuous [Photo: ElenVik/ Shutterstock.com]

Planting mizuna: location and method

While mizuna is flexible in terms of soil and location, it does best in a sunny or semi-shady location with moist, free-draining, loose soil that is rich in nutrients. Japanese mustard greens do not tolerate extended droughts.

You can also grow mizuna in pots. The pot should hold at least half a litre of soil. Generally, pots with a diameter of 10 to 12cm do the trick. Mizuna also grows well in larger planters, such as balcony boxes, which also makes it easier to care for it. When planting mizuna in a pot, use a loose, nutrient-rich soil such as our Plantura Organic Tomato & Vegetable Compost. It already contains fertiliser and is peat-free, which saves over 60% CO₂ compared to conventional, peat composts. For better drainage, mix about 30% coarser materials such as perlite or expanded clay granules into the soil.

Organic Tomato & Vegetable Compost, 40L
Organic Tomato & Vegetable Compost, 40L
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  • Perfect for tomatoes & other vegetables such as chillies, courgettes & more
  • For strong & healthy plant growth as well as an abundant vegetable harvest
  • Peat-free & organic soil: CO2-saving composition

Mizuna prefers mild to cold temperatures, so grow it early or late in the season. You can even grow it very late, as mizuna is hardy to about -10 °C. If you are harvesting mizuna for its edible flowers instead of its leaves, grow it during the summer.

Tip: as mizuna is ready to harvest after about 30 days, it is a suitable choice as a catch crop in the greenhouse.

mizuna plant growing in round pot
You can easily grow mizuna in a pot [Photo: Peter Turner Photography/ Shutterstock.com]

Between March and August, sow mizuna seeds directly into the flower bed or pot. You can sow them directly because you only need to thin out the seedlings a little, not transplant them. Of course, you can always raise mizuna seedlings beforehand. Start seeds indoors between February and September and transplant outdoors until September. You can start sowing mizuna even earlier if you have a greenhouse or a cold frame around a hot bed.

Either sow the seeds in rows or scatter them into the bed. Space the rows at least 15cm apart from each other, leaving 2 to 3cm between seeds. When broadcasting, thin out the seedlings to maintain a 2 to 3cm spacing. The ideal sowing depth is about 1 to 2cm. At about 15 to 20°C the seeds will germinate within a week.

Tip: due to its pleasant mustard aroma, mizuna is a popular sprout or microgreen. Find out how to grow your own mizuna microgreens and sprouts in our articles.

microgreen mizuna growing on windowsill
You can also grow mizuna as sprouts, or as microgreens as pictured [Photo: uladzimir zgurski/ Shutterstock.com]

Mizuna plant care

Mizuna grows very lush in mild temperatures but tends to flower prematurely in warmer temperatures. If you are after mizuna leaves, ensure you water and pick leaves regularly as this can extend your harvest into summer.

If you want your plants to flower sooner, water them less when the temperatures are high. To collect your own mizuna seeds, wait about a month after flowering. By then, the seed pods will have formed. While you can leave the plants and the pods to ripen in the bed, it is better to cut off the mizuna plants right before the pods have turned completely brown. This way you can prevent mizuna from self-sowing all over the place. Dry the collected plants before tapping the seeds out of their pods. Store in a cool, dark place and the seeds will germinate well for about five years.

Make sure to regularly remove weeds from the crop, so that mizuna does not have to compete for nutrients, water and light. Weeding is easier if you sow the seeds in rows.

harvesting mizuna salad leaves
You can harvest mizuna leaves several times [Photo: Wanessa_p/ Shutterstock.com]

Ensure that mizuna is sufficiently supplied with nutrients when planting by working in some well-rotted manure or slow-release organic fertiliser, such as our Plantura All Purpose Plant Food. Our fertiliser gently releases nutrients to the plant over a few months.

Tip: if you care for it well, you can cut mizuna about five times. This also delays the leafy vegetable going to flower.

How to harvest & use mizuna

You can harvest mizuna lettuce more than once. Pick your first leaves after a few weeks, when they are about 5 to 10cm long. Depending on when the plants were sown, leaf harvest usually ends either with mizuna’s flowering or the first snow or frost. You can still eat mizuna leaves after the plant has flowered, but they have a sharper taste and become chewy. You can continue harvesting mizuna during mild winters. Protect your crop with fleece or place it in cold frames or greenhouses.

To harvest, you can cut off individual leaves as needed. However, it makes more sense to cut mizuna back completely on a regular basis to prevent flowers from forming. Cut off with a sharp knife, taking care not to damage the crown so that new leaves can still form.

Use the leaves as soon as possible after harvesting them. Alternatively, you can keep them in the refrigerator for up to four days.

young mizuna plants in flower bed
The younger leaves are perfect for salads [Photo: Ryoko Fujiwara/ Shutterstock.com]

You can use mizuna in a number of different ways in the kitchen. For example, you can use the young leaves to make mizuna salad, the older greens like spinach and the leaf stalks as garnish. Mizuna is excellent in stir-fries, soups, dips, as well as with its traditional dish, ‘nabemono’, a Japanese hotpot. Along with its mild taste, mizuna’s mustard oils create an aroma somewhere between broccoli and rocket.

Can you eat mizuna raw? Yes, young mizuna leaves are especially delicious raw and taste great in salads.

Are mizuna flowers edible? Yes, mizuna flowers are also edible. The green mizuna flowers are quite robust and can be lightly fried or used in soups.

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