Red Komatsuna, Heirloom Seeds

Red Komatsuna, Heirloom Seeds — The Frost-Hardy Japanese Spinach Mustard That Gets Better After Every Cold Snap

Red Komatsuna (Brassica rapa var. perviridis) — known in Japan as komatsuna (小松菜) — is the workhorse of the Asian greens world dressed in its finest burgundy. A staple of Japanese home gardens for centuries, the red variety brings deep anthocyanin-rich color to the garden and the plate, with a flavor that mellows and sweetens after every touch of frost. Less bitter than many mustard greens, tender, slightly mustardy, and genuinely crowd-pleasing — Red Komatsuna is one of the fastest, most reliable cool-season greens you can grow. Baby leaves ready in just 21–30 days; full heads in 40–50 days. A true cut-and-come-again crop that keeps producing for weeks.

Why Grow Red Komatsuna?

• Blazing fast — baby leaves in 21–30 days, full heads in 40–50 days
• Frost-hardy and frost-sweetened — survives light freezes, flavor improves after cold snaps
• Mild and versatile flavor — less bitter than many mustard greens, tender and crowd-pleasing
• Cut-and-come-again — harvest outer leaves repeatedly for weeks of continuous production
• Antioxidant-rich — deep burgundy-red pigmentation from high anthocyanin content
• Open-pollinated heirloom — save seed year after year

Growing Notes

Direct sow outdoors in early spring or late summer for fall harvest. Succession sow every 2–3 weeks for continuous harvest. Sow seeds ¼ inch deep, 2–3 inches apart for baby leaf; 6–8 inches apart for full heads. Full sun to part shade. Keep soil consistently moist. Harvest outer leaves continuously or cut whole plant at soil level. Watch for flea beetles, aphids, and cabbage worms.

In the Kitchen

Use young leaves raw in salads for a pop of color and mild mustard flavor. Larger leaves shine in stir-fries with garlic and sesame oil, sautéed as a side dish, added to miso soup, or lightly pickled. A staple in Japanese ohitashi — blanched greens with dashi and soy sauce.

Days to maturity: 21–30 days (baby leaf), 40–50 days (full head)
Type: Heirloom, Open-Pollinated, Annual
Spacing: 2–3 inches (baby leaf), 6–8 inches (full head)
Sun: Full sun to part shade
USDA Zones: All U.S. zones