VegetableOnion
Candy Onion
Sweet Onion
Candy Onion is an F1 hybrid that breaks the rules of traditional onion growing, combining the flexibility of both short-day and long-day varieties so you can harvest sweet, mild bulbs almost anywhere in the country. Maturing in roughly 90 days from transplants, this intermediate-day onion thrives across hardiness zones 2-9 and produces large bulbs with thick rings ideal for cooking. Its day-neutral adaptation and reliable performance make it a genuinely adaptable choice for gardeners wrestling with regional growing limitations.
Photo © True Leaf Market(https://www.trueleafmarket.com/products/onion-candy-hybrid-seeds)
Growing Conditions
USDA Zone
2-9
Sunlight
Full Sun
Water
High
Soil
Well-drained, Loose Loam; Loose Texture Aids Root Growth
Preferred Temp55-80°F
Growth Stats
24 in
Height
PeriodBiennial (Grown As Annual)
TypeBulbing - Day-neutral
Spacing
5-6 inches apart
Plant Profile
Sunlight
Full Sun
Water
High
Zones
2-9
Size
24in H x ?in W
Growth
Biennial (Grown As Annual)
Care
High
Hover over chart points for details
Highlights
Candy Onion's real strength lies in its geographic versatility. Unlike traditional onions locked into specific day-length zones, this hybrid germinates reliably between 50 and 85 degrees Fahrenheit and grows compact enough (14-24 inches at maturity) to fit into tight garden spaces or container systems. The mild, sweet flavor and thick-ringed bulb structure make it exceptional for caramelizing or using fresh, and the disease resistance to pink root rot eliminates a common underground threat.
Common Uses
Candy Onion excels in any preparation where sweetness and mild flavor are assets. Use them fresh in slaws, on sandwiches, or grilled whole; their thick rings and large bulbs hold up beautifully to caramelizing for French onion soup or slow-cooked dishes. The reliable bulb size and structure make them particularly valuable for cooking applications where consistent thickness matters visually and texturally.
Growing Timeline
First Bloom
Not Applicable (Harvested Before Flowering)
First Harvest
90-110 Days After Planting
Last Harvest
Determinate
Care Instructions
Start Indoors
Sow seeds indoors 6-8 weeks before your last frost date in 128-cell trays at 1 seed per cell, covering with 1/4 inch of soil. Maintain soil temperature between 50 and 85 degrees Fahrenheit for consistent germination. Transplant seedlings 4 inches apart in rows 12-18 inches apart when they reach transplant size. If tops exceed 5 inches before planting out, clip them back to 3-5 inches to encourage stronger root establishment and prevent transplant shock.
Transplant Outdoors
Harden off transplants gradually before moving them to the garden. Plant out after the last frost date in spring, carefully separating seedlings and placing them in shallow trenches. Space 2 inches apart in rows 12 inches apart. Water in well after transplanting and ensure they establish in cool weather to prevent bolting.
Direct Sow
Direct sow seeds outdoors if preferred. Thin seedlings to the strongest plant when they reach 4-5 inches in height. Note that days to maturity for direct seeding are calculated from sowing date, typically taking closer to 110 days rather than the 90 days from transplants.
Harvesting
Harvest when half to two-thirds of the tops have naturally fallen over; push the remaining foliage down and wait about one week before digging. Harvest during dry weather, as onions harvested in wet conditions are prone to rotting during storage. Lift bulbs carefully from loosened soil, brush off excess earth, and allow them to cure in a warm, well-ventilated space before trimming tops and roots for storage.
Pruning
Trim excessively tall transplant foliage to 3-5 inches at planting time to direct energy into root establishment rather than top growth. As bulbs approach maturity and roughly half the tops naturally fall over, you can push over the remaining foliage to signal final maturation and encourage protective papering. Loosen soil around bulbs gently to encourage drying during this final curing phase.
Growing Calendar
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Companion Planting
Pests & Diseases
Ecology & Traits
Edible
Soil pH Range
6 – 7
Scientific Classification
Allium L.
Family
Liliaceae
Genus
Allium
History & Origin
“Candy is a modern F1 hybrid developed to solve a fundamental problem in onion breeding: the rigid photoperiodic nature of most varieties. Traditional onions are slaves to day length, performing well only in their designated zones. Candy was engineered to combine qualities of both short-day and long-day onions, creating a day-neutral intermediate that gardeners could grow successfully across diverse climates from zone 2 to zone 9. This represented a meaningful shift in home gardener accessibility, moving beyond the geographic luck that had previously determined onion success.”