How to grow Komatsuna
Updated October 2026
Komatsuna, sometimes called Japanese mustard spinach, is a fast, mild Asian green with glossy, spoon-shaped leaves. It is not a spinach but a turnip relative, grown like other Asian greens: sow it through the cool season and pick baby leaves for salads or larger leaves for stir-fries.
📖 Our full guide: How to Grow Komatsuna
Not to be confused with: Komatsuna is not true spinach; it is a brassica related to turnip and bok choy. It is grown the same way as mizuna and other Asian greens.
Where to plant
Komatsuna is a cool-season crop that grows best in the mild, damp weather of spring and fall, in full sun or light shade and soil rich in compost that stays moist. Hot, dry weather and lengthening spring days make it bolt, so give it light shade in warm spells.
- Florida, the Gulf South, Texas, the Desert Southwest and Southern California: sow from fall through late winter, the same season as mustard greens.
- The Mid-South, Mid-Atlantic and Southern Plains: sow in early spring and again from late summer.
- The North, Pacific Northwest and Alaska: sow in spring and again in mid to late summer for fall.
How to plant
- Sow thinly about 1/2 inch deep and keep the soil moist; seed sprouts in about a week.
- Thin seedlings to 4 to 6 inches apart for baby leaves, or about 8 inches for full-size plants.
- Sow small batches every two or three weeks for a steady supply.
- Cover with row cover to keep off flea beetles and cabbage worms.
Watering and feeding
Keep the soil evenly moist, watering in the morning. Dry soil makes leaves tough and strong flavored and hastens bolting. A nitrogen-rich liquid feed keeps growth fast and tender.
Harvesting
Pick baby leaves once plants are 3 to 4 inches tall, or cut whole plants when larger. Cut plants about 2 inches above the ground usually regrow. Use young leaves raw in salads and larger leaves and stems in stir-fries and soups.
Growing in pots
Komatsuna grows well in containers at least 12 inches wide. Keep the mix moist and pick often.
Companion planting
Komatsuna is quick and compact, so it can fill gaps between slower crops. Rotate it with other cabbage-family crops.
Good companions
- Lettuce Another quick cool-season leaf crop for the same bed.
- Bush beans A traditional pairing; beans follow the greens in the same bed as the weather warms.
Keep apart
Avoid planting these close to komatsuna.
- Brassicas Do not follow other cabbage-family crops in the same spot, to limit clubroot and other soil diseases.
Pests and diseases
Komatsuna grows so fast it rarely struggles, but cabbage-family pests can still find it.
Pests to watch for
- Flea beetles Many tiny holes in young leaves.
- Cabbage worms Green caterpillars chewing holes in leaves.
- Slugs Ragged holes on seedlings in damp weather.
Diseases to watch for
- Clubroot Wilting plants with swollen, distorted roots; rotate crops.
Common questions
Is komatsuna the same as spinach?
No. Despite the name mustard spinach, komatsuna is a brassica related to turnip and bok choy. Its leaves cook down like spinach and taste mild with a slight mustard tang.
When should I sow komatsuna?
In cool weather: fall through late winter in the South, and early spring and late summer farther north. Hot, dry weather makes it bolt.
How do I harvest komatsuna?
Pick baby leaves for salads, or cut whole plants about 2 inches above the ground, and they will usually regrow.
Can I grow komatsuna in a pot?
Yes. A container at least 12 inches wide with good potting mix works well; keep it moist.
Why is my komatsuna bolting?
Heat, dry soil and long spring days trigger flowering. Sow in spring and fall, keep the soil moist, and give light shade in warm spells.
Sources we checked: RHS: How to grow mizuna and mibuna (oriental greens, including komatsuna); Texas A&M AgriLife Extension: Chinese Cabbage and Mustard, Specialty Crops of Texas; UF/IFAS EDIS: Florida Vegetable Gardening Guide (VH021).
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