3 Best Onion Seeds for Long Day Climates That Northern Growers Trust
Discover 3 top onion varieties perfect for northern climates with 14+ daylight hours. Sweet Spanish Utah Jumbo, Walla Walla Sweet & Yellow Globe Danvers thrive in long day conditions.
Growing onions in long day climates requires the right varieties that’ll thrive in your extended daylight hours. Most gardeners struggle with choosing onion seeds that actually produce quality bulbs in regions with 14+ hours of summer daylight. The bottom line: Three specific onion varieties consistently deliver exceptional results in northern climates – and we’ll show you exactly which ones to plant for the best harvest.
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Understanding Long Day Onion Varieties and Climate Requirements
Long day onions respond to extended summer daylight by forming bulbs when they receive 14-16 hours of light daily. Understanding these varieties helps you maximize your harvest in northern regions where traditional onion seeds often fail to develop properly.
What Makes an Onion Variety Suitable for Long Day Climates
Long day onion varieties require 14-16 hours of daylight to trigger bulbing, making them perfect for northern latitudes above 37°N. These cultivars have genetic programming that responds to extended photoperiods rather than temperature changes. Unlike short day varieties that bulb with 10-12 hours of light, long day onions won’t form bulbs until summer’s peak daylight hours arrive in your region.
Daylight Hour Requirements for Optimal Bulb Development
Your onions need consistent 14+ hour days for 4-6 weeks to develop full-sized bulbs in long day climates. Peak bulbing occurs when daylight reaches 15-16 hours during summer solstice periods. Insufficient daylight hours result in thick necks, small bulbs, or complete bulbing failure, which explains why southern onion varieties disappoint northern gardeners year after year.
Geographic Regions That Benefit from Long Day Onion Seeds
Northern states including Minnesota, Wisconsin, Maine, and Washington provide ideal conditions for long day onion cultivation. Canadian provinces and northern European regions with latitudes above 45°N excel with these varieties. Southern gardeners in Florida, Texas, or Georgia should choose short day onions instead, as long day varieties won’t bulb properly in their shorter daylight conditions.
Sweet Spanish Utah Jumbo: The Giant of Long Day Onion Seeds
You’ll get massive onions with this variety – I’ve grown them for over a decade in northern climates. These giants produce the biggest bulbs of any long day variety I’ve tried.
Exceptional Size and Mild Flavor Profile
Sweet Spanish Utah Jumbo produces onions weighing 1-2 pounds when grown properly. The mild, sweet flavor makes them perfect for fresh eating and cooking applications.
You’ll find these onions less pungent than storage varieties, with a crisp texture that holds up well in salads and sandwiches. Their size makes them ideal for stuffing recipes too.
Growing Requirements and Planting Timeline
Start seeds indoors 10-12 weeks before your last frost date for best results. Transplant seedlings outside 2-3 weeks before the final frost when soil reaches 50°F.
These onions need 14-16 hours of daylight to trigger bulbing properly. Plant them in full sun with well-draining soil enriched with compost for optimal growth.
Expected Harvest Yields and Storage Capabilities
Expect 8-12 large onions per square foot when properly spaced 4-6 inches apart. Each plant typically produces one bulb weighing 12-32 ounces at harvest time.
Storage life runs 2-4 months in cool, dry conditions due to their high water content. Use these onions first since they don’t keep as long as firmer storage varieties.
Walla Walla Sweet: The Premium Choice for Long Day Gardens
Walla Walla Sweet stands as the gold standard among long day onions, delivering exceptional flavor and reliable performance in northern climates. This Washington state native has earned its reputation through decades of consistent results in challenging growing conditions.
Heritage Variety with Superior Taste Characteristics
Walla Walla Sweet delivers unmatched flavor complexity that sets it apart from commercial varieties. This heritage onion produces large, flattened bulbs with remarkably mild, sweet taste even when eaten raw. You’ll notice the distinctive low sulfur content that makes these onions tear-free to slice and perfect for fresh applications. The flavor develops exceptional depth when cooked, caramelizing beautifully without becoming overpowering or bitter.
Optimal Growing Conditions and Care Instructions
Start Walla Walla Sweet seeds indoors 12-14 weeks before your last frost date for best results. These onions require consistent moisture throughout their 110-day growing season and perform best in well-draining soil with pH between 6.0-7.0. Transplant seedlings when soil reaches 45°F, spacing them 4-6 inches apart in rows. You’ll need to provide steady water during bulb formation but reduce watering as harvest approaches to prevent splitting.
Market Value and Culinary Applications
Fresh Walla Walla Sweet onions command premium prices at farmers markets, often selling for $8-12 per pound. Their exceptional storage life of 6-8 months when properly cured makes them valuable for year-round use. You can showcase these onions in gourmet cooking applications where their mild sweetness shines – from caramelized onion tarts to fresh salads. Their reputation alone draws customers who specifically seek out this variety for special occasions and holiday cooking.
Yellow Globe Danvers: The Reliable All-Purpose Long Day Onion
Yellow Globe Danvers stands as the workhorse of long day onion varieties, delivering consistent performance across diverse northern growing conditions. This heirloom variety has earned its reputation through decades of reliable harvests in challenging climates.
Proven Performance in Northern Growing Regions
Yellow Globe Danvers thrives in USDA zones 3-7, consistently producing 3-4 inch bulbs even in unpredictable weather patterns. You’ll find this variety performs exceptionally well from Minnesota’s harsh springs to Maine’s coastal conditions. The 110-day maturity period aligns perfectly with northern growing seasons, requiring minimal coddling compared to more temperamental varieties. Commercial growers in Wisconsin and Michigan rely on this cultivar specifically because it tolerates temperature fluctuations that destroy other long day varieties.
Disease Resistance and Storage Longevity
This variety offers outstanding resistance to pink root disease and downy mildew, two common problems in humid northern climates. You’ll appreciate the natural disease tolerance when wet springs challenge your onion patch. Properly cured Yellow Globe Danvers store for 8-10 months in cool, dry conditions without sprouting or rotting. The thick, bronze-colored skin creates an excellent protective barrier, making these onions ideal for root cellars or unheated storage areas where temperatures remain between 32-40°F.
Versatile Uses in Kitchen and Commercial Applications
Yellow Globe Danvers delivers a balanced pungency that works equally well for fresh eating and cooking applications. You’ll find the moderate sulfur content provides excellent flavor depth without overwhelming heat. These onions caramelize beautifully for French onion soup while maintaining enough bite for fresh salsas and salads. Market gardeners appreciate the uniform size and attractive appearance, with these onions commanding premium prices at farmers markets due to their reputation for consistent quality and storage reliability.
Planting and Care Tips for Long Day Onion Success
Long day onion success hinges on timing, soil preparation, and consistent care throughout their extended growing season. Your attention to detail during these critical phases determines whether you’ll harvest premium bulbs or face disappointing results.
Soil Preparation and Fertilization Requirements
Prepare well-draining soil with a pH between 6.0-7.0 for optimal nutrient uptake. I’ve learned that heavy clay soils lead to misshapen bulbs, while sandy loam produces the best results.
Work 2-3 inches of compost into your beds before planting. Apply a balanced 10-10-10 fertilizer at planting, then side-dress with nitrogen when shoots reach 6 inches tall. Stop nitrogen feeding 6 weeks before harvest to prevent soft necks.
Nourish your lawn and garden with Southern Ag 10-10-10 All Purpose Fertilizer. This granular formula provides balanced nutrients for healthy plant growth.
Watering Schedules and Seasonal Maintenance
Maintain consistent moisture throughout the growing season without waterlogging the soil. I water deeply twice weekly during spring, increasing to every other day during hot summer months.
Begin reducing water when tops start yellowing in mid-summer. Stop watering completely 2-3 weeks before harvest to allow proper curing. Inconsistent watering creates splitting and reduces storage life significantly.
Common Challenges and Problem-Solving Strategies
Thrips and onion maggots pose the biggest threats to long day varieties. I use row covers during early growth and beneficial nematodes for soil-dwelling pests.
Bolting happens when plants experience stress or temperature swings. Plant at proper timing and maintain consistent moisture to prevent premature flowering. Remove any flower stalks immediately to redirect energy into bulb development.
Conclusion
With these three exceptional varieties in your gardening toolkit you’re well-equipped to achieve outstanding onion harvests in your long day climate. Each variety brings unique strengths to your garden whether you prioritize size flavor or storage capability.
Your success will depend on proper timing consistent care and selecting the variety that best matches your growing goals. Remember that long day onions reward patience and attention to detail with impressive yields that’ll keep your kitchen stocked for months.
Start planning your next season’s onion crop now and you’ll be amazed at the quality and quantity these proven varieties can deliver in your northern garden.
Frequently Asked Questions
What are long day onions and when should I plant them?
Long day onions require 14-16 hours of daylight to trigger bulbing, making them perfect for northern climates above 37°N latitude. Start seeds indoors 10-14 weeks before your last frost date, then transplant when soil temperatures reach 50°F. These varieties are genetically programmed to respond to extended photoperiods during summer months.
Which onion varieties perform best in northern climates?
The top three varieties for long day climates are Sweet Spanish Utah Jumbo (producing 1-2 pound bulbs), Walla Walla Sweet (premium flavor with 6-8 month storage), and Yellow Globe Danvers (reliable heirloom with 8-10 month storage). Each offers unique benefits for different growing goals and storage needs.
How much space do I need to grow long day onions?
You can expect 8-12 large onions per square foot when growing varieties like Sweet Spanish Utah Jumbo. Plant onions 4-6 inches apart in rows spaced 12 inches apart. This spacing allows adequate room for bulb development while maximizing your garden’s productivity.
What soil conditions do long day onions need?
Long day onions thrive in well-draining soil with a pH between 6.0-7.0. Incorporate compost before planting and ensure consistent moisture without waterlogging. Apply balanced fertilizer at planting, then side-dress with nitrogen as plants grow. Good drainage prevents root rot and promotes healthy bulb development.
How long do long day onions take to mature?
Most long day onion varieties require 110 days from transplant to harvest. They need consistent long days (14-16 hours) for 4-6 weeks during peak bulbing season. Peak bulbing typically occurs around the summer solstice when daylight hours are longest in northern regions.
How should I store harvested long day onions?
Storage life varies by variety: Sweet Spanish Utah Jumbo lasts 2-4 months, Walla Walla Sweet stores 6-8 months, and Yellow Globe Danvers can last 8-10 months. Cure onions in a warm, dry, well-ventilated area for 2-3 weeks, then store in cool, dry conditions with good air circulation.
Can I grow long day onions in southern climates?
No, long day onions are not suitable for southern regions below 37°N latitude. Southern areas don’t receive the necessary 14-16 hours of daylight needed to trigger bulbing. Instead, southern gardeners should choose short day varieties that bulb with only 10-12 hours of light.
