VegetableOnion
Red Grano Onion
Red Grano Onion is a short-day bulbing variety that thrives in southern gardens, producing medium-sized red onions with a crisp, mild flavor in 110 to 119 days. This open-pollinated heirloom grows 14 to 24 inches tall and adapts well to diverse growing environments, from garden beds to containers. Hardy across zones 2 through 9, it's a practical choice for gardeners seeking reliable reds that work equally well fresh or cooked.
Photo © True Leaf Market
Growing Conditions
USDA Zone
2-9
Sunlight
Full Sun
Water
Moderate
Soil
Well-drained, Fertile Loam, Moderately Rich
Growth Stats
24 in
Height
Spacing
3
Plant Profile
Sunlight
Full Sun
Water
Moderate
Zones
2-9
Size
24in H x ?in W
Growth
—
Care
High
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Highlights
The real appeal here is the mildness paired with crispness, a combination that makes Red Grano exceptional for raw applications where you want onion's presence without aggressive bite. As a short-day variety specifically bred for southern climates, it's already adapted to what many gardeners struggle with; plant it where long-day reds would fail to bulb properly. The fact that it thrives in containers as readily as in-ground beds gives you flexibility most heirloom onions don't offer.
Common Uses
Red Grano's mild, crisp character makes it the onion for raw applications where you want flavor without harshness. Slice it thin for salads, layer it on hamburgers, or dice it into salsas and fresh condiments where its sweetness complements rather than dominates. The mild profile also makes it approachable for cooking applications where you're building a softer onion flavor into dishes, though its true strength lies in applications that showcase its fresh crispness.
Growing Timeline
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Care Instructions
Start Indoors
Start seeds indoors 8 to 10 weeks before your last spring frost. Sow at a depth of 1/4 inch in seed-starting mix, maintain soil temperature around 70 degrees Fahrenheit, and provide bright light as soon as seedlings emerge. Keep seedlings consistently moist but not waterlogged.
Transplant Outdoors
Harden off seedlings over 7 to 10 days by gradually exposing them to outdoor conditions. Transplant once they reach 4 to 6 inches tall and soil has warmed to 50 degrees Fahrenheit or above. Space transplants 3 inches apart in rows 15 inches apart, planting deep enough so the base of the seedling is at soil level.
Direct Sow
Direct sow seeds outdoors in early spring as soon as soil is workable, or in fall in southern regions where winters are mild. Sow seeds 1/4 inch deep, spacing them 1 to 2 inches apart, then thin seedlings to 3 inches apart once they've developed true leaves.
Harvesting
Harvest Red Grano onions when the foliage begins to brown and fall over naturally, typically 110 to 119 days after planting. This toppling signals that bulbs have matured and are ready to lift. Gently dig bulbs from the soil, brush away excess earth, and lay them in a warm, dry location with good air circulation to cure for 2 to 3 weeks until the outer papery layers dry completely.
Growing Calendar
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Companion Planting
Ecology & Traits
Edible
Scientific Classification
Allium cepa
Family
Amaryllidaceae
Genus
Allium
Native Status
L48 (I)
History & Origin
“Red Grano emerged as a short-day cultivar selected and refined for southern American agriculture, where day length challenges traditional northern onion varieties. As an open-pollinated heirloom, it represents the kind of practical crop improvement that developed through generations of seed saving in regions where it performs best. The variety has been preserved and distributed through seed catalogs precisely because it solves a real geographic problem: giving southern gardeners a reliably bulbing red onion when conventional varieties simply won't form proper bulbs.”