Komatsuna Seeds | Japanese Mustard Spinach | Cold Hardy & Heat Tolerant | All-Season Green

Komatsuna Seeds – Japanese Mustard Spinach

Komatsuna (Brassica rapa var. perviridis) is one of Japan’s most versatile and widely grown leafy vegetables — commonly known in the U.S. as Japanese Mustard Spinach. Cold hardy and heat tolerant, it thrives across all four seasons and is ready to harvest in as little as 35 days from sowing in warm conditions. With a mild, sweet flavor and tender stalks, komatsuna is equally at home in salads, stir-fries, soups, and pickles.

A fast-growing, highly productive green for home gardeners and market growers alike. Succession sow every 2 weeks for a continuous, year-round harvest.

Variety Details

• Species: Brassica rapa var. perviridis
• Common Name: Japanese Mustard Spinach, Komatsuna
• Type: Annual — cool and warm season
• Flavor: Mild, sweet, tender
• Days to Maturity: 35–45 days (warm conditions); longer in cool weather
• Seed Count: Approx. 11,300 seeds per oz
• Suitable Climates: Temperate, subtropical, and cool-season gardens
• Cold Hardy: Yes — tolerates frost
• Heat Tolerant: Yes — more bolt-resistant than many Asian greens

Planting Guide

• Prefers mild to cool temperatures but tolerates a wide range of conditions.
• Prepare fertile, well-drained soil enriched with compost before sowing.
• Sow seeds in late spring/early summer after last frost, or in late summer/early fall for an autumn crop.
• Avoid planting during peak summer heat for best leaf quality and flavor.
• Sow every 2 weeks for a continuous, cut-and-come-again harvest.
• Direct sow thinly; thin seedlings to 4–6 inches apart.
• Keep soil consistently moist; fertilize lightly as needed throughout the season.

Harvesting

• Harvest leaves and young stems when plants reach approximately 8 inches tall.
• Young leaves are best for salads; larger leaves and stems are ideal for stir-fries and pickling.
• Cut outer leaves to encourage continued production, or harvest the whole plant at soil level.
• Flower shoots are also edible — harvest before fully open for a tender, flavorful bonus crop.

Culinary Uses

• Fresh in salads — young leaves are mild and sweet
• Stir-fries with garlic, ginger, soy sauce, or oyster sauce
• Miso soup and hot pot dishes
• Salt pickling — a traditional Japanese preparation (tsukemono)
• Blanched as a side dish or added to noodle dishes
• Smoothies and juices — a nutritious spinach substitute