Growing Mizuna: How to Cultivate Fresh Superfood Greens

I sow mizuna on the first cool breath of spring and again as summer yawns, because it sprints in chill and pouts in heat. A light frost kissed my November bed last year and the greens came out sweeter, with that peppery snap I crave.

Mizuna is a Japanese brassica, Brassica rapa var. japonica, with feathery leaves, quick maturity, and a clean mustard bite. It behaves like arugula’s calm cousin and spins from seed to salad in a blink.

“Cruciferous vegetables contain glucosinolates that are broken down into biologically active compounds that have been studied for cancer-preventive effects.” Harvard T.H. Chan School of Public Health

I grow it for speed, for resilience, and because it takes dressings like a pro. It also thrives in tight spaces, which makes it a star for small urban beds and balcony boxes.

Growing Mizuna shines at 45 to 70 F, which is 7 to 21 C, with light frost tolerance. Heat and long days push it to bolt, so I chase cool weather and partial shade in summer.

• Early spring sowing: as soon as soil can be worked and night temps stabilize above 30 F, which is about minus 1 C.
• Late summer sowing: 6 to 8 weeks before first frost for a fall and winter cut in mild zones.
• Overwintering: in zones 7 to 9, tuck under row cover or a cold frame for steady salads.

Tilth matters. I aim for pH 6.0 to 7.5, crumbly soil, and steady moisture.

• Work in 1 to 2 inches, which is 2.5 to 5 cm, of finished compost before planting.
• If your soil test is light on nitrogen, add a balanced organic fertilizer around 5-5-5 at 1 to 2 pounds per 100 square feet, which is 0.5 to 1 kg per 9.3 m².
• Avoid fresh manure, since it can fuel pests and off flavors.

I direct sow for baby leaf and set transplants for tidy, full heads. Both work, just pick your finish line.

1. Make shallow furrows 0.25 inch deep, which is 6 mm, and water the drill.
2. Sow thickly for baby leaf or 2 to 3 seeds every 4 inches, which is 10 cm, for heads.
3. Cover lightly, firm, then lay insect netting right after planting.

Thin baby-leaf beds aggressively, snack on the thinnings, and keep spacing around 1 inch, which is 2.5 cm. For heads, thin to 8 to 10 inches, which is 20 to 25 cm, between plants.

“Floating row covers exclude pests and also reduce frost injury to tender crops.” University of California Statewide IPM Program

Mizuna turns tender with steady moisture. I give about 1 inch of water per week, which is 25 mm, split into light, frequent drinks in heat.

Mulch thinly with shredded leaves or straw to keep soil cool. In July, a 30 percent shade cloth slows bolting without stretching plants.

Mizuna grows beautifully in planters at least 6 inches deep, which is 15 cm. A 24 inch box, which is 60 cm, can feed two people with weekly cuts.

• Use a peat-free or coir-based mix with added compost for nutrition.
• Water daily in hot spells, since containers dry fast.
• For indoor sets, run lights 14 to 16 hours with a moderate intensity around 150 to 250 µmol m⁻² s⁻¹.

In NFT or deep water culture, I run pH 5.8 to 6.2 and an EC near 1.5 to 1.8 mS/cm. Keep solution temps 60 to 68 F, which is 16 to 20 C, to avoid root stress.

This crop tolerates close spacing on rails for baby leaf, then tastes clean and bright. I harvest roots-on for longer shelf life.

Flea beetles pockmark leaves fast. I cover beds at sowing, since prevention beats chasing beetles with sprays.

• Aphids: blast with water, then use insecticidal soap or a neem rotation if needed.
• Caterpillars like cabbage loopers: scout undersides and use Bt kurstaki on small larvae.
• Slugs: set beer traps or iron phosphate baits, water at sunrise not at dusk.
• Harlequin bug hot spots: hand pick early and remove nearby wild mustards.
• Clubroot and downy mildew: rotate out of Brassica beds for 3 to 4 years, improve drainage, and lime if soil is sour.

Mizuna is a modest feeder, but it pays you back if fed consistently. I side-dress with a light sprinkle of compost or fish-based fertilizer at 3 weeks.

Leaf color tells the tale. Pale leaves signal low nitrogen, deep green with good gloss means you nailed it.

For baby leaf, I cut at 3 to 5 inches, which is 7.5 to 13 cm, and it regrows two or three times. For full heads, I slice at the crown when rosettes hit 8 to 12 inches, which is 20 to 30 cm.

“Baby leaves in 21 to 25 days, full heads in 40 to 50 days.” Johnny’s Selected Seeds trial notes

Rinse, spin dry, then bag with a paper towel and refrigerate at 34 to 38 F, which is 1 to 3 C. Stored dry and cold, my cuts hold a week and often longer.

“Most leafy greens keep best near 32 F with high relative humidity.” UC Davis Postharvest Technology Center

• Toss with citrus, sesame oil, and a pinch of flaky salt for a two-minute salad.
• Flash it in a hot pan with garlic and shiitakes for a ramen topper.
• Blend with parsley, lemon, and toasted almonds for a peppery pesto.
• Quick-pickle stems with rice vinegar, sugar, and ginger, then pile on rice bowls.

• Kyona: classic green, fine-cut leaves, fast and forgiving.
• Early Mizuna: quick baby leaf, tight habit for containers.
• Red Kingdom F1: burgundy midribs and leaves in cool weather, gorgeous in mixes.
• Mizuna Kyoto: mild flavor with sturdy petioles for bunching.
• Close cousin Mibuna: strap-like leaves and milder taste, handy for stir-fries.

For baby-leaf production, look for varieties described as slow to bolt. For bunching, pick lines noted for cold tolerance and uniform heads.

• Row cover or insect netting, light grade around 0.5 oz per sq yd, to block flea beetles while allowing airflow.
• Shade cloth at 30 percent for summer sowings to delay bolting.
• Soil test kit to dial pH and nutrients correctly.
• 6 inch deep containers with saucers for balcony growing and a quality potting mix.
• Harvest knife or shears with a shallow curve for clean cuts, plus a salad spinner.

• Holes in leaves: you missed flea beetles, so cover at planting and use yellow sticky cards to monitor.
• Bitter leaves: heat stress, so add shade and water in the early morning.
• Plants shoot up with flowers: they hit long days and warm nights, so resow for fall and thin for airflow.
• Slow growth in rich soil: pH drift or compaction, so test pH and loosen the bed with a garden fork.

I sow small patches every 10 to 14 days in spring and again from late summer to early fall. The trick is to stagger, harvest hard, and replant with the same bed prep each time.

Pair mizuna with scallions, dill, and cilantro to confuse pests and keep bed space tight. Keep it away from other Brassicas in your rotation to avoid shared diseases and flea beetle pressure.

Mizuna is Brassica rapa, so it cross-pollinates with turnips, bok choy, napa cabbage, and komatsuna. Isolate by at least 0.25 mile, which is 400 m, if you want seed that stays true.

“For Brassica rapa, maintain generous isolation distances to prevent crossing with related crops.” Seed Savers Exchange

• Tatsoi: spoon-shaped leaves, silky texture, outstanding in cold frames.
• Komatsuna: broader leaves and gentle mustard flavor, extremely heat tolerant for summer greens.
• Arugula: spicier, faster, and happy in poor soil, but more flea beetle prone.
• Mustard greens: bigger leaves and bolder heat, better cooked than raw for many palates.

A 3 by 6 foot bed, which is 0.9 by 1.8 m, gave me six heavy cuts over ten weeks with two sowings. The best patch sat under netting with a thin straw mulch and took water from a soaker hose set low and slow.

• Harvard T.H. Chan School of Public Health, Cruciferous Vegetables overview.
• University of California Statewide IPM Program, Vegetables and row cover guidance.
• UC Davis Postharvest Technology Center, Leafy greens storage recommendations.
• Johnny’s Selected Seeds, crop sheets and days-to-maturity data.
• Seed Savers Exchange, Brassica rapa seed saving guidelines.

Growing Mizuna rewards you with peppery crunch and vitamin-packed greens, all for the price of a few seeds and some patience. Give it rich soil and steady moisture, and you’ll be harvesting salad gold in no time. Pick leaves young for tenderness, and don’t be afraid to cut and come again—mizuna bounces back strong. Mix it up with other leafy favorites like kale or swiss chard for variety in your beds and on your plate. If pests show up, a little vigilance and row cover go a long way. In a world full of fussy crops, mizuna keeps it real—fast, forgiving, and always fresh. Grow it once, and you’ll wonder how you ever did without.