Ruby Onion is a deep burgundy bulbing onion that reaches full maturity in 100 days, delivering medium to large globed bulbs with firm, pungent red flesh. Bred around 1965, this open-pollinated heirloom thrives across hardiness zones 2 through 9 and adapts readily to gardens, raised beds, containers, and even greenhouses. Its combination of striking color, heavy yields, and reliable cold tolerance makes it a standout for gardeners seeking both productivity and visual drama in the kitchen.
Full Sun
Moderate
2-9
24in H x ?in W
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Moderate
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The deep burgundy flesh that persists all the way through, paired with excellent yields and a globed shape that's distinctly full and satisfying, gives Ruby Onion real presence in the garden and on the plate. Its cold-hardy nature and open-pollinated heritage mean you can save seeds year after year, building a strain adapted to your own growing conditions. The firm, pungent character suits both raw slicing and long, slow cooking where the color intensifies.
Ruby Onions work beautifully sliced raw in salads where their deep color creates visual contrast, and their pungent character adds backbone to vinaigrettes. They excel in slow-roasted or caramelized preparations where the natural sugars deepen and the flesh becomes tender and sweet. Their firm texture and vibrant color also make them excellent for pickling, where they hold their shape and visual appeal through storage.
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Start seeds indoors 8 to 10 weeks before your last spring frost, keeping soil between 50 and 70°F for reliable germination. Transplant seedlings to containers once they develop their first true leaves, providing bright light to keep them from becoming leggy. Harden off seedlings over 7 to 10 days before moving them to the garden.
Transplant Ruby Onion seedlings outdoors after the last frost date when soil temperatures reliably stay above 50°F. Space transplants 3 inches apart in rows 15 inches wide. Water gently after transplanting to settle soil around the roots and eliminate air pockets.
Direct sow seeds outdoors in spring as soon as soil can be worked, or in late summer for fall/winter harvest in warmer zones. Plant seeds 1/4 inch deep and keep the seedbed consistently moist until germination, which typically occurs within 7 to 10 days at optimal temperatures. Thin seedlings as they emerge to final spacing of 3 inches apart.
Harvest Ruby Onions when the tops begin to yellow and fall over, typically 100 to 109 days from sowing, though exact timing depends on your specific growing conditions and day length. Dig bulbs carefully to avoid bruising and allow them to cure in a warm, dry, well-ventilated space for 2 to 3 weeks before storage. You'll know they're ready when the outer papery skin dries completely and the tops have fully dried.
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“Ruby Onion was released around 1965, arriving during a period when American gardeners were rediscovering the flavor and yield potential of heirloom bulbing onions. Its designation as a long-day variety reflects careful breeding to suit northern climates where it performs reliably. As an open-pollinated cultivar, it has persisted through seed-saving networks and is now preserved by home gardeners and heritage seed companies who value its combination of beauty, vigor, and consistent productivity.”