Buttercup winter squash emerged from a happy accident at North Dakota State University in the 1920s, when researchers discovered an exceptional cross between Essex and Quality varieties. This dusty aquamarine turban squash with bright orange flesh was specifically bred as a sweet potato substitute for northern growers, weighing 3-3.5 pounds each with a satiny texture and unmistakable chestnut flavor. Taking 90-100 days to mature, it thrives in full sun with moderate water and proved so successful that university researchers declared each fruit the perfect family serving size for 5-6 people with no leftovers.
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Full Sun
Moderate
3-10
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Born from necessity in the challenging North Dakota growing season, this heirloom represents pre-industrialized breeding at its finest, where flavor and texture mattered as much as yield. The researchers conducted exhaustive taste tests to develop this exceptional variety with natural insect resistance and early maturity. Its creamy, nutritious flesh made the perfect substitute for semi-tropical sweet potatoes that northern growers couldn't grow, solving a real problem with elegant simplicity.
With its creamy texture and mild sweet flavor reminiscent of chestnuts, Buttercup excels as a sweet potato substitute in northern cuisine. The nutritious starchy flesh works beautifully in baked preparations, soups, and any dish where you'd traditionally use sweet potatoes. Each 3-3.5 pound fruit provides the perfect family serving size, designed specifically to feed 5-6 people in one meal without leftovers.
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Start seeds indoors 3-4 weeks before your last expected frost in 4-inch pots. Plant seeds 1 inch deep in fertile, loose soil enriched with compost. Maintain soil temperatures between 70-85°F for germination, which typically occurs in 7-12 days.
Transplant carefully after all danger of frost has passed and soil temperatures reach at least 65°F. Work a shovelful of compost into each hill before transplanting, taking care not to disturb the roots.
Direct sow after soil warms to 65°F and all frost danger has passed. In warm climates, a second planting can be made in midsummer for late fall harvest. Plant in fertile, loose soil enriched with compost or well-rotted manure.
Harvest when the rinds are hard and skin color is deep and uniform, typically after 90-100 days. Leave fruit on the vine until fully mature, then cut the stem leaving 2-4 inches remaining. Gently wash harvested squash in a sanitizing solution of 10 parts water to 1 part bleach before storage.
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“In the 1920s, researchers at North Dakota State University were searching for a sweet potato substitute that could thrive in their notoriously brief growing season. They discovered a chance cross between two varieties, Essex and Quality, that showed exceptional promise. The researchers named their happy accident Buttercup and began selecting for the traits that mattered most to northern growers: early maturity, natural insect resistance, and exceptional flavor. Through exhaustive taste tests and careful selection, they developed the dusty aquamarine-colored fruit we know today. This represents a shining example of pre-industrialized breeding, where flavor and texture were considered equally important as yield and vigor, creating a variety specifically tailored to solve real problems for regional growers.”