How to Grow Southport White Onion
Wikimedia Commons
Southport White Onion
Allium cepa 'Southport White'
vegetableSouthport White is a classic American heirloom onion variety known for its pure white, globe-shaped bulbs and mild, sweet flavor. These medium to large bulbs store exceptionally well and have been a gardener's favorite since the 1800s. Ideal for fresh eating, cooking, and storage.
When should you plant Southport White Onion in your zone?
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Example Southport White Onion timeline · Pittsburgh, PA (Zone 6b)
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Plant Southport White Onion
Around Apr 17Near Pittsburgh's average last spring frost.
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Tend & protect
Late spring–summerWatering, feeding, and pest-watch reminders.
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Harvest Southport White Onion
Around Aug 5≈ 110 days after planting
Sample dates for Pittsburgh, PA. Sign up to get exact Southport White Onion dates for your own zip code.
Growing Conditions
Soil
Growing Zones
Find your zone →Thrives in zones 3-9; best performance in cooler to moderate climates with 120-130 day growing season
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Seedling
2-3 weeksThin, grass-like green shoots emerge from soil; plants are delicate and pencil-thin
Keep consistently moist; thin seedlings to proper spacing early; provide bright light if growing indoors
Vegetative/Leaf Development
6-8 weeksMultiple green shoots develop into a small clump of tubular leaves; roots establish underground
Maintain consistent watering and regular fertilizing every 2-3 weeks; ensure full sun exposure; remove any flower stalks immediately
Bulb Initiation
3-4 weeksBase of plant begins to swell as bulb starts forming; green foliage continues to expand
Continue regular feeding; mulch lightly to keep roots cool; ensure soil stays consistently moist but not waterlogged
Bulb Development & Maturation
4-5 weeksBulb enlarges significantly and becomes globe-shaped; outer layers turn white and papery; foliage begins to yellow and weaken
Reduce watering frequency; stop fertilizing; mulch helps prevent sunscald on white bulbs; allow foliage to yellow naturally
Harvest Ready
1-2 weeksFoliage topples over and dries; bulbs are firm with dry, papery white skin; neck is completely dry
Stop watering entirely in final week; harvest when 50-75% of tops have fallen over
Companion Planting
Plan your garden →Plant with:
Avoid planting near:
Common Pests
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Use row covers in spring; maintain good drainage to prevent larvae; rotate crops; remove affected bulbs immediately
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Spray with neem oil or insecticidal soap; increase watering to create humid conditions; remove heavily infested plants
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Ensure excellent drainage; cure bulbs properly with good air circulation; practice 3-4 year crop rotation; remove diseased bulbs
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Provide good air circulation; water at soil level only; apply sulfur or copper fungicide in cool, wet springs; remove infected foliage
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Hand-pick early morning or evening; use beer traps; copper barriers; encourage beneficial predators
Uses
Fresh Eating & Mild Flavor
CulinarySouthport White onions are exceptionally mild and sweet, making them ideal for fresh eating raw in salads, salsas, and slaws. Their crisp texture and subtle flavor are prized by cooks who want onion flavor without the harsh bite. [source]
Cooking & Caramelizing
CulinaryThese bulbs caramelize beautifully when sautéed, developing rich sweetness. Their firm texture holds up well in stews, casseroles, and roasted vegetable dishes. [source]
Superior Storage
HouseholdSouthport Whites are known as an excellent storage variety, keeping 6-8 months in cool, dry conditions with minimal spoilage. Their papery skin and firm flesh make them ideal for winter pantries. [source]
Quercetin & Antioxidants
MedicinalLike all onions, Southport White contains quercetin and other compounds with potential anti-inflammatory and antioxidant properties. Traditional uses include supporting immune health and general wellness. [source]
Natural Dye
CraftThe dry, papery outer skin of white onions can be used to create natural dyes for fabric and yarn, producing warm cream, tan, and gold colors. [source]
This is not medical advice. LizPlants is not a medical resource. Always consult a qualified healthcare professional before using plants medicinally.
Harvest Tips
Harvest when 50-75% of foliage has toppled and turned brown, typically June-July in northern regions. Carefully loosen soil with a fork and pull by hand. Cure in a warm, dry, well-ventilated space (70-80°F) for 2-4 weeks until skin is completely dry and papery. Store in a cool (45-55°F), dark, dry location with good air circulation; properly cured Southport Whites can store 6+ months.
Fun Facts
- 🌱 Southport White is an American heirloom variety that became popular in the late 1800s and was developed in Southport, Connecticut, where it won regional agricultural competitions.
- 🌱 Unlike modern hybrid onions, this open-pollinated variety can be saved for seed, allowing gardeners to maintain and grow their own seed stock year after year.
- 🌱 The white pigmentation in these onions comes from a lack of anthocyanin pigments, making them visually striking and popular for fresh market sales and exhibition at county fairs.
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