Known as "seaweed on land," this Japanese annual transforms gardens with its unique grass-like appearance and distinctive salty, tart flavor. Growing 18-24 inches tall, Oka Hijiki thrives in zones 2-10 and delivers tender, succulent leaves in just 30-39 days. Native to Japan's salt marshes but adaptable to garden soils, this cool-season green offers a taste of the sea with every harvest.
Full Sun
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2-10
24in H x 12in W
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High
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Oka Hijiki stands apart with its extraordinary flavor profile that perfectly mimics seaweed, earning its nickname "seaweed on land." The 12-inch long, matchstick-thin leaves pack impressive nutrition, delivering excellent sources of vitamin A, calcium, and potassium in a plant that grows wild in Japan's coastal marshes. Its remarkable adaptability allows it to thrive across an incredible range from zone 2 to zone 10, while its rapid 30-39 day harvest cycle makes it perfect for succession planting throughout the growing season.
The tender young leaves excel when eaten fresh in salads or lightly steamed, showcasing their distinctive tart, salty flavor with underlying nuttiness. Many gardeners blanch the leaves briefly in salty water, then shock them in ice baths before adding to dishes. The versatile greens can be steamed and served with mustard or vinegar, grown as nutrient-dense microgreens, or even dried and rehydrated for later use, making them valuable for both fresh consumption and food preservation.
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Direct sow between last frost date and early fall. Sow seeds liberally and cover lightly with soil, maintaining consistent moisture. For best results, pre-chill seeds for 7 days at 41°F before planting. Germination occurs at temperatures between 20-30°C over 14 days, with light exposure during 8-hour periods at the higher temperature range improving success.
Harvest young leaves frequently for the best flavor and texture, typically beginning 30-39 days from sowing. Focus on tender, young growth as older leaves become tough and prickly, especially in summer heat. Regular harvesting encourages continued production and maintains the succulent quality that makes this green so prized.
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“This remarkable green grows wild in Japan's salt marshes, where it has been harvested for generations as both a wild food and cultivated crop. Known by many names across Asia including kobu takana, gat, and sawi, it represents a bridge between wild foraging traditions and modern cultivation. Commercial cultivation in Japan has helped preserve this unique plant, bringing the taste of coastal marshlands to inland gardens worldwide.”