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Overview
Allium cepa 'Copra' is Copra onion (Copra yellow storage onion), a biennial grown as an annual for bulb production, 18-24 inches (45-60 cm) tall and 4-6 inches (10-15 cm) wide. Globe-shaped bulbs 3-4 inches (7-10 cm) diameter, 8-12 ounces (225-340 g), with golden-bronze papery skins and pungent white flesh. A long-day storage onion: requires 14-16 hours of daylight for bulbing (latitudes above 36°N). F1 hybrid — seed does not produce true to type. Stores 8-10 months at 32-40°F (0-4°C) — one of the longest-storing yellow onions. The well-defined thin neck dries completely during curing — the key to long storage. Blue-green hollow tubular foliage. In the amaryllis family (Amaryllidaceae). Pungent raw, mellows when cooked. Start seed indoors 10-12 weeks before last frost. Harvest when 50-75% of tops have fallen and yellowed (100-110 days from transplant). Cure 2-4 weeks. Not a sweet onion — the pungent flavor is a limitation for raw eating. All Allium contain thiosulfates: toxic to dogs, cats, and horses. Onion maggot (Delia antiqua) and thrips are primary pests. Deer-resistant. Full sun. Annual. Growth rate is moderate.
Native Range
F1 hybrid cultivar. The species A. cepa is native to Central Asia (Iran, Afghanistan, Pakistan).Suggested Uses
Grown in vegetable gardens and containers of at least 3 gallons (11 L). Long-storing yellow onion (8-10 months). Long-day type. Pungent — cooking onion. F1 hybrid. Toxic to pets. Deer-resistant. Annual.How to Identify
Appearance
Size & Dimensions
Height1'6" - 2'
Width/Spread4" - 6"
Reaches mature size in approximately 1 years
Bloom Information
Biennial: flowers in the second year if overwintered — white spherical umbels. Grown as an annual for bulb production. Cut flower scapes at the base if they appear.Detailed Descriptions
Flower Description
White spherical umbels — only if allowed to bolt; undesirableFoliage Description
Blue-green, hollow tubular, 0.5-0.75 inch (12-18 mm) diameter; yellows at maturityGrowing Conditions
Sun Requirements
Requires 6-12 hours of direct sunlight daily
• Full Sun: 6+ hours of direct sunlight
• Partial Shade: 3-6 hours of direct sunlight
• Full Shade: Less than 3 hours of direct sunlight
Care & Maintenance
Care Guide
Full sun (6+ hours). Well-drained soil pH 6.0-7.0. Long-day onion — 14-16 hours daylight. Start seed 10-12 weeks indoors. Consistent moisture during bulb swelling. Reduce watering as tops yellow. Stores 8-10 months. F1 hybrid. All Allium toxic to pets. Deer-resistant. Annual.Pruning
Cut flower scapes at the base if they appear. Do not cut green foliage during growth. Harvest when 50-75% of tops have fallen. Trim tops to 1 inch (2.5 cm), roots to 0.25 inch (6 mm). Cure 2-4 weeks.Maintenance Level
lowContainer Growing
✓ Suitable for container growing
Minimum container size: 3 gallons