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Copra Onion

Allium cepa 'Copra'

The gold standard for long-storage onions, Copra delivers outstanding keeping quality with bulbs storing 8-12 months when properly cured. This reliable variety produces uniform, dense bulbs with excellent flavor that intensifies during storage. A must-have for gardeners seeking year-round onion self-sufficiency.

Harvest

104-110d

Days to harvest

📅

Sun

Full sun

☀️

Zones

5–10

USDA hardiness

🗺️

Height

12-18 inches

📏

Planting Timeline

Zone:

Jan

Feb

Mar

Apr

May

Jun

Jul

Aug

Sep

Oct

Nov

Dec

Direct Sow

Harvest

Direct Sow

Harvest

Showing dates for Copra Onion in USDA Zone 7

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Zone Map

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Copra Onion · Zones 5–10

What grows well in Zone 7? →

Growing Details

Difficulty

Easy

Spacing4-6 inches

SoilWell-drained, fertile soil with good organic content

pH6.2-6.8

Water1 inch per week, reduce before harvest

SeasonCool season

FlavorSharp, pungent flavor that mellows when cooked

ColorGolden brown skin with white flesh

Size3-4 inches diameter

Zone-by-Zone Planting Calendar

Zone	Indoor Start	Transplant	Direct Sow	Harvest
Zone 3	—	—	May – June	August – October
Zone 4	—	—	April – June	August – October
Zone 5	—	—	April – May	July – November
Zone 6	—	—	April – May	July – November
Zone 7	—	—	March – May	July – November
Zone 8	—	—	March – April	June – December
Zone 9	—	—	February – March	May – December
Zone 10	—	—	January – March	May – December

Complete Growing Guide

Light: Full sun (6 or more hours of direct sunlight a day). Soil: High Organic Matter, Loam (Silt), Sand. Soil pH: Alkaline (>8.0), Neutral (6.0-8.0). Drainage: Good Drainage, Moist. Height: 1 ft. 0 in. - 1 ft. 6 in.. Spread: 0 ft. 6 in. - 1 ft. 0 in.. Spacing: Less than 12 inches, 12 inches-3 feet. Maintenance: Medium. Regions: Coastal, Mountains, Piedmont.

Harvesting

Flowers wither and convert to bulblets

Type: Capsule.

Harvest time: Summer

Bloom time: Summer

Storage & Preservation

Proper curing is essential for Copra's legendary storage potential. Spread harvested onions in a single layer in a well-ventilated, dry location (garage, shed, or covered porch) for 2-4 weeks until necks are completely dry and papery. Once cured, trim roots and tops to 1 inch, then store in mesh bags or crates in a cool (32-40°F), dry location with good air circulation.

Properly cured Copra onions store 8-12 months at 32-40°F with 60-70% humidity. For shorter storage, keep at room temperature for 2-3 months. Freeze diced onions in portions for cooking, or dehydrate sliced onions for seasoning. Their intense flavor makes them excellent for pickling or fermenting into onion relish.

History & Origin

Copra was developed by Johnny's Seeds in the 1990s as a response to gardeners' need for a reliable, long-storage onion variety suited to diverse growing conditions. This intermediate-day hybrid was specifically bred to combine the storage qualities of traditional European keeping onions with improved disease resistance and uniform bulb production.

The variety name 'Copra' refers to dried coconut meat, symbolizing the onion's exceptional storage and 'keeping' qualities. Johnny's plant breeders focused on creating an onion that would bridge the gap between short-day southern varieties and long-day northern types, making it adaptable across USDA zones 3-9.

Since its introduction, Copra has become the gold standard for home gardeners seeking year-round onion self-sufficiency, earning recognition from seed companies and extension services nationwide for its consistent performance and remarkable shelf life that rivals commercial storage varieties.

Advantages

+Disease resistance: Black Walnut, Deer, Rabbits

Considerations

-Toxic: Low severity

Companion Plants

Plant Together

Carrots

Onions repel carrot flies while carrots help break up soil for onion bulb development

Tomatoes

Onions deter aphids and hornworms from tomatoes while improving their flavor

Brassicas (Cabbage, Broccoli)

Onions repel cabbage worms, flea beetles, and other brassica pests

Lettuce

Onions provide pest protection and don't compete for nutrients due to different root depths

Peppers

Onions deter aphids and other soft-bodied insects that damage pepper plants

Strawberries

Onions repel slugs and other pests while not competing for growing space

Marigolds

Both plants repel nematodes and various garden pests when grown together

Parsley

Attracts beneficial insects and doesn't compete with onions for nutrients

Keep Apart

Beans

Onions can inhibit bean growth and nitrogen fixation

Peas

Onions stunt pea growth and interfere with their nitrogen-fixing ability

Asparagus

Onions can inhibit asparagus growth and reduce spear production

Nutrition Facts

Calories

40kcal(2%)

Protein

1.1g(2%)

Fiber

1.7g(6%)

Carbs

9.34g(3%)

Fat

0.1g(0%)

Vitamin C

7.4mg(8%)

Vitamin A

0mcg(0%)

Vitamin K

0.4mcg(0%)

Iron

0.21mg(1%)

Calcium

23mg(2%)

Potassium

146mg(3%)

Per 100g serving. % Daily Value based on 2,000 calorie diet. Source: USDA FoodData Central (FDC #170000)

Pests & Disease Resistance

Resistance

Good resistance to pink root and fusarium basal rot

Common Pests

Onion thrips, onion maggots, wireworms

Diseases

Downy mildew, purple blotch, bacterial soft rot

Frequently Asked Questions

How long does Copra onion take to grow from seed?▼

Copra onions take 104-110 days from transplanting to harvest. When starting from seed indoors, add 10-12 weeks for the seedling stage, making the total time from seed to harvest approximately 6-7 months. Direct-seeded onions may take slightly longer depending on soil temperature and growing conditions.

Can you grow Copra onions in containers?▼

Yes, Copra onions grow well in containers at least 8-10 inches deep with excellent drainage. Use a 20-gallon container for multiple plants, spacing them 3-4 inches apart. Container growing allows better soil control but requires more consistent watering and fertilizing than ground planting.

What does Copra onion taste like?▼

Fresh Copra onions have a sharp, pungent flavor that's quite intense when raw. During storage, the flavor mellows and sweetens while maintaining good cooking qualities. When cooked, they develop a rich, savory taste that's excellent for soups, stews, and general culinary use.

When should I plant Copra onion seeds?▼

Start Copra seeds indoors 10-12 weeks before your last frost date for transplanting 2-3 weeks before the last frost. For direct seeding, plant when soil temperature reaches 50°F consistently. In most areas, this means starting seeds indoors in January-February for spring transplanting.

Is Copra onion good for beginners?▼

Yes, Copra is excellent for beginners due to its reliable performance, disease resistance, and forgiving nature. The main challenge is the long growing season and proper curing technique, but the variety's consistent bulb formation and clear harvest indicators make it easier than many onion varieties.

How do you cure Copra onions for long storage?▼

Cure Copra onions by spreading them in a single layer in a well-ventilated, dry area for 2-4 weeks until necks are completely dry and papery. Avoid direct sunlight and ensure good air circulation. Properly cured onions will have tight, dry necks and papery outer skins before storage.