Stir-fries in spring and salads in the middle of summer both have one thing in common – the peppery and wonderful vegetable that is mizuna! An addition to the garden that produces early in the season and can tolerate the type of weather fluctuations that gardener nightmares are made of, these wonderful little plants will give you harvest after harvest of delicious greens for months. Growing mizuna greens should be on the garden plan of any family who loves to cook.
Native to the Kansai region of Japan, these seeds have now traveled the globe and are grown in zones USDA 3-10. They were also grown in outer space as part of a vegetable growing experiment on the International Space Station!
These distinctive plants spring up from the soil almost overnight and make great salad, stir-fries, and shabu-shabu among other dishes. Traditionally, many chefs have pickled the mizuna’s tender green leaves to make a variety of side dishes. Some plant mizuna varieties that are purple because of the presence of anthocyanin, the same compound that turns blueberries blue!
Similar to the taste of arugula, you can tell them apart by the distinct mustard aftertaste of the mizuna. This plant does especially well when grown in rotation with legumes. A heavy nitrogen feeder, it will happily soak up the nitrogen that legumes ‘fix’ in the soil.
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Quick Care Guide
| Common Name(s) | Mizuna; potherb mustard; California peppergrass; spider mustard; kyona; shui cai; Japanese mustard |
| Scientific Name | Brassica rapa var. niposinica or Brassica rapa var. japonica |
| Days to Harvest | 20-40 |
| Light | Full sun to partial shade |
| Water: | 1 inch per week |
| Soil | Well-drained soil rich in nitrogen |
| Fertilizer | Seaweed or fish emulsion |
| Pests | Flea beetles; aphids |
| Diseases | Damping-off |
All About Mizuna
Japanese mizuna greens have long been a staple of Asian cooking, as the plant originated in Japan. Like other greens mizuna go by a long list of names like Japanese mustard, potherb mustard, California peppergrass, shui kai, and spider mustard. A peppery and spicy vegetable, this versatile addition to the garden can be grown year-round in some regions and is valued for its wonderful nutritional content.
A member of the brassica family, it’s actually in the same family as cabbage. Unlike other brassicas, mizuna can tolerate heat and cold weather to a better extent.
Mizuna greens are foot-tall clumps of green serrated leaves with thin stems. While some cultivars also produce purple leaves like ‘Mizuna Crimson Tide’, this plant is added to gardens almost exclusively for its leaves. A quick grower, small grey seeds quickly sprout into sturdy leaves in small circular clumps. Near the end of the plant’s life, it will bolt and go to seed-producing small yellow flowers on long green spikes above the plant.
Planting Mizuna
It’s best (and easy!) to grow mizuna from seed. A small round grey seed roughly the size of a lentil, it’s easy to sow. Sow seeds to 1/4th to 1/2 inch deep in well-drained rich soil. Plant in rows 18-24 inches apart. After sowing seeds, plants will germinate in 4-7 days if temps are between 45-85 degrees. Once the seedlings reach 1 inch in height, thin to 6 inches apart. You can expect a harvest 3 to 6 weeks after germination.
It’s best to plan on planting your seeds two weeks after the last frost, but if grown in areas with no frost, mizuna can be planted in the garden in late summer.
Care
A hardy choice, mizuna has a few basic growing requirements. Plant mizuna in a sunny area with well-draining and fertilized soil and you’re already off to a great start!
Sun and Temperature
A great choice for a northern garden that gets the occasional late frost, mizuna is a hardy little green that once established can take a sudden and unexpected frost. As such, it can be one of the earliest crops in the garden. Likewise, for a southern garden, these plants can tolerate hotter weather than most other greens.
Able to grow in USDA zones 3-10; mizuna grows best in the full sun of the day but can tolerate partial shade. Requiring 10-12 hours of sunlight, try planting in an area that will receive little if any shade. Additionally, sow several inches apart so that fully grown plants don’t shade out plants that are regenerating themselves.
Water and Humidity
Moist soil is the key to happy mizuna! Its leaves contain a great deal of water, and if the soil dries out, it can cause your mizuna to go to seed. Mizuna greens need to be watered in the morning, preferably on a drip system. Early in its life, try watering your mizuna twice a week to keep the soil evenly wet. After the leaves grow and shade the soil surrounding itself, decrease to once a week.
Water one inch a week, and add a light mulch of straw or fine wood chips around the seedlings. In spring and fall, reduce watering if the soil becomes waterlogged. In Summer, monitor the soil if it dries out quickly in heat or warm winds.
Soil
It’s best to grow mizuna greens in well-drained rich soil. Ideally, amend the soil with compost or sterilized manure before sowing seed. Mizuna thrives in most soils but needs a pH of between 6.0-7.5. If growing in containers, coco coir is a great choice as it aids in drainage. But again, don’t allow it to dry out as it will start to go to seed.
Fertilizing
Mizuna greens have very simple fertilization requirements. As these plants are grown for their leaves they need a lot of nitrogen! When you first sow your seeds, work well-rotted manure into the soil. This will provide nitrogen early in the plant’s life. After about one month, apply a liquid seaweed solution or fish emulsion to keep the mizuna growing well. Reapply every month or so or as needed.
Pruning
Mizuna greens are a very rewarding crop. As it’s easy to grow mizuna, once established, mizuna will tolerate several rounds of cutting. Once the leaves reach between 10-12 inches in length, cut the stems to about 1 inch off the ground. It’s best to use a sharp or serrated knife and cut parallel to the ground.
After cutting, water the area and ensure the soil stays moist. In a few short weeks, you’ll be able to harvest again!
Propagation
Mizuna greens are exclusively grown from seed. A fast-growing harvest, either sow seed or purchase seedlings. Seeds are hardy as well! They have great viability when saved for up to 4 years!
Harvesting and Storing
Harvesting mizuna is as simple as snipping a delicious green leaf. A great cut and come again option, this Japanese mustard is a bountiful addition to the garden.
Harvesting
Mizuna, like any green, can be eaten at even the earliest stages of growth. However, it’s best to harvest mizuna between 20 and 40 days after germination. Many gardeners like this Japanese green when it’s still in a relatively young stage as tender greens. Others prefer to let this green get upwards of 10 inches long before harvesting. Cut the greens at the base of the leaf leaving inner growth undisturbed.
Storing
Once picked, store unwashed mizuna greens in a salad spinner or breathable bag in the fridge. Make sure to avoid storing in a sealed plastic bag as this will cause the green leaves to immediately begin to decay.
For long-term storage, try pickling your greens. Japanese chefs and home cooks have long been pickling these sturdy greens and using them as a condiment. Pickling is a common method of preservation in Asian cooking. Many recipes abound for pickled side dishes. A short search will bring up lots of delicious options!
Troubleshooting
You’re in luck! Mizuna greens are a relatively easy plant to grow. Monitor outdoor temps, keep your soil moist, and use a row cover and you’ll likely have a trouble-free crop in a month or so!
Growing Problems
Mizuna greens are a very hardy green. Able to withstand warm summer weather better than most other greens, you can harvest mizuna up into the 80’s. Keep in mind however that it can bolt. Bolting happens when your mizuna tries to reproduce and grows seeds for another generation of plants.
To avoid bolting, ensure that the soil around the base is continuously moist as dryness will trigger the plant to reproduce. Alternatively, if you’re expecting weather over 85 degrees, you can expect to see the end of harvest.
Pests
Flea beetles are the primary pest you’ll come across when caring for mizuna. These beetles lay their eggs on the soil surface not too far from the stalks. The larvae hatch and eat holes in the stems and leaves. To prevent flea beetles, cover your crop with a row cover, this prevents the beetles from physically laying their eggs anywhere near your plants.
Aphids are small light green bugs about 1/8th of an inch long. They usually appear in groups and suck the sap of the plant. They multiply rapidly and can kill a plant by eating too much and introducing disease into the weakened plant. Use insecticidal soap & pyrethrum to control.
Diseases
Mizuna greens are not very susceptible to disease. The one exception is damping off, a disease most likely to happen when you sow seeds in trays indoors. Damping-off presents as a fuzzy mold on top of the soil and stems that appear shrunken or eaten. There is no cure, but it can be prevented by increasing ventilation or spreading sulfur powder over the affected areas to stop the spread to surrounding seedlings.
Frequently Asked Questions
Q: How long does it take to grow mizuna?
A: About 40 days.
Q: Is mizuna a lettuce?
A: Mizuna isn’t lettuce. They come from different plant families but are used in similar ways in cooking.
Q: Is mizuna the same as arugula?
A: No. These are two different plants, although both are peppery tasting greens.
