Oslo stands apart as a high-quality organic fall leek that transforms from seed to harvest in just 110 days from transplant. This F1 hybrid brings exceptional reliability to the leek patch, thriving in fertile soil with a pH between 6.0-7.0 and demanding consistent moisture throughout its growing season. What makes Oslo special is its perfectly timed maturation for fall harvest, when cooler weather concentrates its flavors and the soil stays workably moist for the extended storage methods that make leeks such garden treasures.
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Oslo delivers the robust, substantial harvest that serious leek growers demand, maturing in 110 days from transplant with the reliable performance only F1 breeding can provide. This variety excels in fall gardens where its timing aligns perfectly with autumn storage techniques, from root cellars to humid cold storage that can extend the harvest for weeks. The 4-inch spacing and compact 12-inch rows make efficient use of garden space while producing leeks substantial enough to anchor soups and stews through winter months.
Oslo leeks shine in the hearty dishes of cooler seasons, where their substantial texture and complex onion-family flavor elevate soups and stews beyond the ordinary. These versatile vegetables excel when grilled whole to caramelize their natural sugars, or sliced thin into delicate slivers that add sophisticated flavor to omelets and fresh salads. Packed with vitamins K and A, they bridge the gap between raw applications where their milder, more tender character shines in finger-sized harvests, and cooked preparations that benefit from their full mature diameter and robust flavor.
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Sow seeds in flats 10-12 weeks before the last frost date, planting 1/4 inch deep and spacing seeds 1/4 inch apart, or start in plug flats and thin to one plant per cell. Seeds can also be sown with up to 10-12 seeds per 4-6 inch pot for later separation.
Beginning in late spring when seedlings reach approximately 8 inches tall and pencil-thick diameter, transplant into holes dibbled 6 inches deep with only 2-3 inches of leaves extending above soil surface. Space transplants 6 inches apart in rows at least 12 inches apart, and avoid firming soil around transplants, allowing irrigation or rain to naturally fill the dibble holes. If tops reach over 5 inches before transplant time, cut back to 3 inches.
When direct sowing, thin to the strongest plant when seedlings reach 4-5 inches tall.
Harvest Oslo leeks anytime they reach 1/2 inch in diameter or larger for the best texture and flavor, though finger-sized leeks offer milder, more tender qualities perfect for fresh salads. Unlike onions, leek tops do not die back to signal maturity, so harvest timing depends on desired size and intended use. These leeks can remain in the ground to be harvested as needed until the ground freezes, and in mild winter areas, they may overwinter in the garden for extended fresh harvest.
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