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Allium cepa 'Copra'
Copra Onion
Cultivar of garden origin: 'Copra' is an F1 hybrid yellow storage onion bred for long shelf life, golden-bronze papery skin, and the well-defined thin neck character that supports the long storage; the species {Allium cepa} is native to Central Asia (Iran, Afghanistan, Pakistan) where the wild ancestor still grows in dry rocky habitats; the long-day photoperiod requirement (14-16 hours daylight for bulbing) restricts cultivation to latitudes above 36°N in North America
Overview
Allium cepa 'Copra' is Copra onion (Copra yellow storage onion), a biennial in the amaryllis family (Amaryllidaceae) grown as an annual for bulb production, reaching 18-24 inches (45-60 cm) tall with a 4-6 inch (10-15 cm) spread. The cultivar produces globe-shaped bulbs 3-4 inches (7-10 cm) in diameter weighing 8-12 ounces (225-340 g) with golden-bronze papery skins and pungent white flesh. Long-day storage onion that requires 14-16 hours of daylight for bulbing, restricting cultivation to latitudes above 36°N. F1 hybrid — seed does not produce true to type. Bulbs hold storage quality 8-10 months at 32-40°F (0-4°C) and rank among the longer-storing yellow onion cultivars. The well-defined thin neck dries completely during curing — the thin-neck character is the key to long storage since thicker necks retain moisture and rot during storage. Foliage is blue-green hollow tubular. Pungent raw, the flavor 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 raw flavor is a tradeoff against the long storage life. All Allium contain thiosulfates that are toxic to dogs, cats, and horses. Onion maggot (Delia antiqua) and thrips are the primary pests. Deer-resistant. Full sun. Annual. Growth rate is moderate.
Native Range
F1 hybrid cultivar. The species Allium 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 holding 8-10 months. Long-day type for latitudes above 36°N. Pungent — a cooking onion rather than a raw-eating onion. F1 hybrid. Toxic to pets. Deer-resistant. Annual. Not suited to short-day southern latitudes (below 36°N) where the photoperiod does not trigger bulbing.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 — small white flowers in spherical umbels. Grown as an annual for bulb production. Cut flower scapes at the base if any appear during the growing cycle to keep the plant's energy directed into bulb development.Detailed Descriptions
Flower Description
White spherical umbels — only if plants overwinter and bolt; bolting is undesirable in a bulb crop and the harvest goal is to lift the bulbs before any flower stalks emergeFoliage Description
Blue-green hollow tubular leaves 0.5-0.75 inch (12-18 mm) in diameter; yellows at maturity as the bulb completes developmentGrowing 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 per day). Well-drained soil at pH 6.0-7.0. Long-day onion requiring 14-16 hours of daylight for bulbing. Start seed indoors 10-12 weeks before last frost. Consistent moisture during bulb swelling, then reduce watering as tops yellow and the plant approaches maturity. Bulbs hold storage quality 8-10 months. F1 hybrid. All Allium are toxic to pets. Deer-resistant. Annual.Pruning
Cut flower scapes at the base if any appear during the growing cycle. Do not cut the green foliage during growth since photosynthesis from the leaves drives bulb expansion. Harvest when 50-75% of tops have fallen and yellowed. Trim tops to 1 inch (2.5 cm) and roots to 0.25 inch (6 mm). Cure 2-4 weeks in a warm dry well-ventilated location before storage.Maintenance Level
lowContainer Growing
✓ Suitable for container growing
Minimum container size: 3 gallons
⚠️ Toxicity Warning
Toxic to petsPlanting Guide
Botanical Flashcard
