Japanese Giant Garnet Mustard is a striking baby leaf variety that brings deep purplish-red color and mild, distinct flavor to your garden. Originally developed in Japan, these seeds come directly from their source country and deliver uniform, rounded leaves that develop their rich color early and hold it all season long. Fast-maturing in just 30-39 days, this frost-tolerant annual thrives in hardiness zones 2-10 and reaches 18-24 inches tall, making it equally at home in cool-season gardens and summer plantings.
Full Sun
Moderate
2-10
24in H x ?in W
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Low
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The deep purplish-red leaves of this variety emerge uniformly colored and stay vibrant from spring through summer, giving your salad bowl consistent visual appeal. True to its Japanese heritage, each rounded leaf delivers a mild but distinctive mustard flavor that complements rather than overwhelms other greens. At 30-39 days to harvest, you're picking fresh baby leaves in less than five and a half weeks, perfect for gardeners who want quick returns without sacrificing variety or beauty.
Japanese Giant Garnet is grown primarily as a baby leaf green for fresh eating. The mild flavor and tender texture at harvest maturity make it suited to mixed salads where you want mustard's character without heat. The attractive purplish-red color adds visual interest to salad bowls and vegetable platters, making it valuable for gardeners interested in colorful, nutrient-dense greens rather than traditional spicy mustard preparations.
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Direct sow seeds when soil temperature reaches 50-75 degrees Fahrenheit. For spring crops, sow as soon as soil is workable. Since this variety is frost-tolerant, you can plant earlier than you might expect. For fall crops, sow 6-8 weeks before your first expected frost to allow 30-39 days to baby leaf maturity before cold weather.
Begin harvesting when the rounded leaves reach baby leaf stage, typically 20-30 days after sowing for the most tender growth. Look for uniform purplish-red coloring as a visual cue that the leaves are ready; the color develops early and indicates flavor maturity. Pinch or cut outer leaves first, allowing the center to continue producing, or harvest entire plants if you prefer. The variety retains its color through the entire harvest window, so timing is flexible based on your preference for tenderness.
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“This cultivar was developed in Japan and represents the seed-saving traditions of Japanese horticultural breeding. The seeds come directly from Japan, carrying forward generations of careful selection for the specific combination of early color development, leaf shape, and mild flavor that define this variety. Unlike many modern mustard cultivars, Japanese Giant Garnet is open-pollinated, meaning gardeners can save seeds from their own plants and maintain this direct connection to Japanese growing traditions season after season.”