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Miike Giant Mustard is a broad-leafed heirloom that breaks the mold for mustard greens by actually earning its name. Growing 18 to 24 inches tall with striking ruby veins running through its loosely-headed leaves, this Japanese cultivar reaches full maturity in just 40 to 49 days. It thrives in full sun across hardiness zones 2 through 10, making it one of the most cold-hardy greens you can plant. While it works well for spring planting in cooler climates, gardeners in warmer regions will find it shines as a fall crop, when cooler temperatures allow it to develop its full, impressive size.
Full Sun
Moderate
2-10
24in H x ?in W
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High
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This mustard gets genuinely big compared to standard greens, with plants reaching up to two feet tall and needing slightly wider spacing to reach their potential. The ruby-veined leaves create a striking visual presence in the garden, and the plant matures quickly enough to fit into spring or fall rotations without monopolizing garden space. Its cold hardiness across zones 2 through 10 means gardeners from Minnesota to Georgia can grow it, and the non-GMO heirloom status speaks to gardeners interested in seed saving and preserving open-pollinated varieties.
As a fresh cooking green, Miike Giant Mustard works in stir-fries, sautés, and braised dishes where its size accommodates longer cooking without complete disintegration. The broad leaves and robust structure also make it suitable for salads when harvested young and tender, though mature leaves lean toward cooked preparations. Its rapid maturity fits well into succession planting strategies for gardeners who want continuous harvests of fresh greens throughout the growing season.
No timeline data available yet for this variety.
Direct sow seeds into prepared garden beds in early spring as soon as soil can be worked, or in late summer for a fall harvest in warm climates. Press seeds into moist soil and keep the bed consistently moist until seedlings emerge.
Begin harvesting outer leaves once plants are 4 to 6 inches tall, which typically occurs within the first two to three weeks. For full-sized heads, wait until plants reach 18 inches tall, usually around 40 to 49 days from sowing. Harvest in the morning after dew has dried but before heat builds, when leaves are most turgid and flavorful. Pick outer leaves first to encourage continued production, or cut the entire head at the soil line if you prefer a single large harvest.
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“Miike Giant Mustard carries a Japanese heritage in its name and genetics. As an heirloom variety classified as Brassica juncea var rugosa, it represents a lineage of mustards cultivated in Japan and preserved through generations of seed saving. The variety's journey to Western gardens reflects the broader movement of home gardeners and seed companies recovering and distributing open-pollinated varieties that had been overshadowed by modern hybrids.”