Rossa Di Milano is a striking Italian heirloom onion that brings both beauty and flavor to the kitchen garden. These flat-topped bulbs develop a distinctive burnished plum skin and grow to baseball size with remarkable uniformity. Taking 110 days from transplants to reach maturity, this long-day variety rewards patient gardeners with a melt-in-the-mouth caramelized flavor when cooked, balancing sweetness with a gentle pungency that deepens as the bulbs age. Thrips-resistant and exceptionally long-storing, it's a reliable choice for gardeners in cooler climates who start seeds indoors in early spring.
Full Sun
Moderate
3-10
18in H x 4in W
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Moderate
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These Italian heirlooms deliver an exceptional balance of sweet and savory when cooked, with bulbs that caramelize into silky tenderness on the stove. The burnished plum-colored skins are visually striking in the garden and at harvest, and the variety's natural resistance to thrips means fewer pest pressures than many other onion cultivars. With proper storage, a single season's harvest feeds you through winter; these bulbs hold their flavor and texture for up to six months in cool conditions.
These onions shine when caramelized, transforming into sweet, glossy layers perfect for French onion soup, creamy pasta dishes, or slow-roasted vegetable platters. Their mild, mellow character when cooked makes them excellent for anyone who finds raw onion too sharp; they're equally at home sliced thin into salads once you've developed a taste for the fresher pungency. The bulbs store exceptionally well, making them a practical choice for cooks who want to preserve summer's harvest for winter cooking.
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Sow seeds indoors 6 to 8 weeks before your last spring frost date (some sources recommend starting as early as 12 weeks before last frost for optimal establishment). Sow one seed per cell in 128-cell trays, covering with 1/4 inch of soil. Space seeds about 1 inch apart if sowing in rows. Keep soil consistently moist but not waterlogged, and maintain good air circulation to prevent damping off, a common problem in onion seedlings. Seeds germinate best in cool conditions.
Transplant seedlings outdoors after the danger of hard frost has passed and soil is workable, typically 4 to 6 weeks after sowing indoors. Harden off seedlings gradually over 7 to 10 days by exposing them to increasing periods of outdoor conditions. Space transplants 4 inches apart in rows 12 to 18 inches apart. You may clip the tops back to 5 inches at transplanting time to manage tall, unruly growth. Soil temperature should be at least 50 degrees Fahrenheit.
Harvest Rossa Di Milano when bulbs reach baseball size, typically around 110 days after transplanting, though some sources indicate 100 days to maturity. The bulbs are ready when the tops begin to yellow and fall over naturally; you can gently push over remaining tops by hand to signal ripeness. Cut or pull the bulbs carefully, then cure them in a warm, dry location with good air circulation for 2 to 3 weeks before final storage. Clip off the dried tops and roots before long-term storage.
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“Rossa Di Milano represents generations of Italian onion cultivation, particularly prized in the Lombardy region around Milan. As an open-pollinated heirloom, seed savers have maintained this variety through careful selection and replanting, preserving both its distinctive flat-topped shape and complex flavor profile. Johnny's Selected Seeds notes this as their 'superior strain of this classic, long-day Italian OP,' suggesting the variety has been refined and stabilized through thoughtful breeding work while retaining its open-pollinated nature, allowing home gardeners to save seeds and continue the tradition.”