Crop guide · The cabbage family

How to grow Mizuna

A fast, feathery Japanese mustard green with mild peppery leaves that regrow after cutting and hold up through light frost.

Brassica rapa var. nipposinica · also called Japanese mustard greens, kyona

Full sun Beginner Frost-hardy
Sun
Full sun
Afternoon shade once temps stay above 80 °F (27 °C) keeps leaves tender and delays bolting
Frost
Hardy
Takes frost into the mid-20s F unprotected
Spacing
6 in
15 cm between plants
Sow depth
¼ in
6 mm
To harvest
21–45 days
counted from sowing
Timing

When to plant Mizuna

Windows are counted from the average date of your last spring frost.

Fall planting:8–10 weeks before first frost, repeating every 2 weeks.
Winter planting:under a cold frame or low tunnel in mild-winter areas.
Too late?Stop spring sowings once days regularly top 80 °F (27 °C) — plants bolt (shift from leaf growth to flowering) before they fill out. Sow again in late summer.
Background

Why grow Mizuna

Ready for a first cut in about three weeks and a full harvest in five, mizuna gives salad greens far earlier than head lettuce and tolerates cool, dim conditions that stall most crops.

A little history. A leafy form of the same species as turnip and bok choy, selected in Japan for deeply notched leaves and many slender stalks rather than a swollen root.

The season, step by step

From planting to harvest

Sow outside

4–5 weeks before last frost

Sow seeds ¼ inch (6 mm) deep, and aim for 6 inches (15 cm) between plants once thinned. Sow shallow and keep the top half-inch moist until sprouts show; break any surface crust after heavy rain. Seedlings emerge in 4–8 days.

Best soil temp 60–70 °F (16–21 °C) Minimum 40 °F (4 °C) Emerges in 4–8 days

Water and feed

All season

Water every 2–3 days in warm weather; less in cool, damp spells. Water when the top inch of soil feels dry. Aim for about 1 inch per week including rain.

Work compost in before sowing, then side-dress once after the first cut. What to use: balanced 5–5-5 organic or a nitrogen-leaning liquid feed.

Prune and maintain

As it grows

Snip out any flower stalk as soon as you see it. Removing it buys a week or two of leaf harvest before the plant quits.

Harvest and store

21–45 days from sowing

It's ready when outer leaves reach 4–8 in and the plant has a full spray of notched leaves. Cut before any central stalk starts to lengthen. For repeat cuts, take outer leaves with scissors 1 in above the crown, leaving the center growing. For a full harvest, cut the whole rosette 1–2 in above the soil; it will resprout once or twice.

Wash, spin dry, and refrigerate loose in a bag with a dry paper towel for 5–7 days. Do not store wet; the thin leaves collapse.

Companions

Good neighbours, bad neighbours

Plant it with

Wasabi

Both are cabbage-family plants that want cool air, steady moisture, and dappled light, so mizuna makes an easy filler in the shaded, damp ground wasabi needs. Watch for shared cabbage-family pests, and note that mizuna finishes in weeks while wasabi takes years.

Garden Pea

A pea trellis on the south side throws light shade across the bed by late spring, which can hold off bolting for an extra week or two once days warm. The pea roots also leave nitrogen behind for whatever follows next season.

Sweet Alyssum

Its low mats of tiny flowers reliably draw in hoverflies, whose larvae eat aphids. Since aphids are mizuna's steadiest greenhouse and spring problem, an alyssum edging earns its space.

Radish

Flea beetles often hit radish leaves first, sparing nearby mizuna. This only helps if you pull and dispose of the chewed radish tops rather than leaving a beetle nursery in the bed.

Lettuce

Same sowing dates, same water needs, same shallow rooting, and different pest lists. Interplanting the two gives a mixed cut-and-come-again bed without either crop crowding the other.

Chives

A strong-smelling onion-family edging can make it harder for aphids and cabbage moths that hunt by smell to home in on the crop. The effect is partial, not a substitute for netting.

Keep it away from

Fennel

Fennel roots release compounds that stunt most garden vegetables, and shallow-rooted greens sitting alongside it grow poorly. Plant fennel in its own corner, where its flowers can still feed hoverflies and tiny parasitic wasps.

Peppermint

Mint spreads by runners and will thread through a low bed of greens within one season, making clean cutting impossible. Grow it in a sunken pot or a separate bed.

The Cabbage Family

Kale, cabbage, broccoli, and turnips share flea beetles, cabbage worms, and clubroot with mizuna. A solid block of cabbage-family plants concentrates all three; break the planting up and keep the rotation gap honest.

Sunflower

Sunflowers root widely and shallowly and cast heavy shade, out-muscling a low leaf crop for water and light by midsummer. Keep mizuna at least 3 ft clear on the sunny side.

See Mizuna in the full companion chart →

Crop rotation

After this crop

Family rest

Give the cabbage family 4 years away from this spot before any of its relatives return.

Good next crops

The tomato family, the pea and bean family or the carrot family thrive in this ground next season.

A heavy feeder that leaves little behind — expect depleted nitrogen and possible flea beetle or clubroot carryover. Keep cabbage-family crops out of this bed for 4 years. Follow with peas or beans to rebuild nitrogen, or with tomatoes, carrots, or parsnips.

Trouble to watch for

Pests and diseases

Pests

Flea beetle

Sign
Dozens of round shot-holes across young leaves; tiny black beetles hop off when disturbed.
Fix
Cover the bed with fine insect netting from the day you sow, sealing the edges with soil.

Cabbage worm

Sign
Ragged chewed edges and dark green pellets in the leaf crown; velvety green caterpillars.
Fix
Pick caterpillars off by hand twice a week, or spray a caterpillar-specific biological insecticide.

Aphids

Sign
Clusters of gray-green insects packed into leaf crevices and along stalks; sticky leaves.
Fix
Blast colonies off with a hard water spray, repeating every 3 days until they stop returning.

Slugs and snails

Sign
Ragged holes and silvery slime trails on lower leaves, worst after rain.
Fix
Clear mulch and boards from around plants and set iron phosphate bait pellets at dusk.

Diseases

Downy mildew

Sign
Pale yellow blotches on upper leaf surfaces with fine gray-purple fuzz underneath in cool, wet weather.
Prevent
Thin for airflow, water the soil rather than the leaves, and harvest crowded plantings young.

White rust

Sign
Raised chalky-white blisters on leaf undersides with yellow spots above.
Prevent
Space plants at a full 6 in, avoid overhead watering in cool damp spells, and clear infected leaves.

Clubroot

Sign
Plants wilt in midday heat and never recover size; roots are swollen and distorted when pulled.
Prevent
Keep cabbage-family crops out of infested beds for at least 4 years. Test soil pH first — lime can suppress this disease but will not eradicate it, and over-liming locks out micronutrients.

Damping off

Sign
Seedlings topple at the soil line with a pinched, water-soaked stem.
Prevent
Sow into well-drained soil, avoid watering late in the day, and thin early so leaves dry quickly.
FAQ

Common questions about Mizuna

When should I plant Mizuna?
Spring: 4–5 weeks before last frost, as soon as soil can be worked. Fall: 8–10 weeks before first frost, repeating every 2 weeks.
How long until Mizuna is ready to harvest?
21–45 days, counted from sowing. It's ready when outer leaves reach 4–8 in and the plant has a full spray of notched leaves. Cut before any central stalk starts to lengthen.
Can I grow Mizuna in a container?
Either works — needs only 6–8 in of soil depth, so it suits shallow pots and window boxes. In containers: 8 in deep pot or trough, 12 in wide minimum.
How often should I water Mizuna?
Water every 2–3 days in warm weather; less in cool, damp spells. Water when the top inch of soil feels dry.
How should I store Mizuna after harvest?
Wash, spin dry, and refrigerate loose in a bag with a dry paper towel for 5–7 days. Do not store wet; the thin leaves collapse.
Can Mizuna stay in the ground over winter?
In mild-winter areas, plants sown in early fall hold under a low tunnel and resume growth in late winter, then bolt as days lengthen.

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