Onions are a versatile vegetable that enhances many savory dishes. For home gardeners in northern climates long day onions are ideal. Their growth habits are optimized for the 14+ daylight hours of summer in northern regions. Of all the long day onion types red onions offer the most color and zest. Let’s explore some of the top long day red onion varieties for your garden.
An Overview of Long Day Onions
Long day onion varieties require 14-16 hours of sunlight per day to trigger bulb formation. This makes them suitable for planting in the northern half of the U.S. and Canada. Regions south of 35° latitude have insufficient daylight hours for proper long day onion growth.
Long day onions are typically planted early in spring and harvested in late summer or early fall. Common long day types include yellow white and red onions. Reds offer a splash of color and more pungent flavor than whites or yellows.
Top Long Day Red Onion Varieties
Here are some excellent long day red onion cultivars to grow in your garden:
Red Wing
- Medium to large round red bulbs
- Sweet mild taste
- Stores well up to 5 months
- Resistant to pink root disease
Red Bull
- Uniform deep red medium-sized bulbs
- High yield potential
- Stores 3-4 months
- Good for southern zones as “intermediate day” onion
Red Baron
- Large 4-5 inch bulbs
- Deep red color
- Mildly pungent flavor
- Stores well up to 4 months
Cabernet
- Dark red glossy skin
- Sweet juicy flesh
- Stores well for 2-3 months
- Resists bolting and splitting
Red Comet
- Small to medium bulbs
- Beautiful glossy deep red color
- Medium pungency
- Stores up to 2 months
Rossa Lunga di Firenze
- Italian heirloom with elongated torpedo shape
- Mild sweet flavor
- Stores well for 2-3 months
- Prone to bolting in warmer zones
Red of Florence
- Italian heirloom dating back to 1865
- Large 4-6″ bulbs
- Purplish-red skin and pink rings when sliced
- Sweet mild flavor
- Stores 2-3 months
Growing Conditions for Long Day Red Onions
Most long day onions thrive in full sun and well-drained fertile soil. Add compost or aged manure before planting to enrich the soil. Space onion sets 1-2 inches apart in rows 12-18 inches apart.
Water onion plants regularly to keep the soil moist, especially during bulb formation. Applying mulch helps retain soil moisture. Side dress with a nitrogen fertilizer a few weeks after transplant and again when bulbs start swelling.
Harvesting and Storing Long Day Red Onions
onions should be harvested when about half of the plant has toppled over and the bulbs feel firm. Loosen the bulbs with a garden fork rather than pulling by hand to avoid damaging them.
Cure harvested onions in a warm dry place for 1-2 weeks before trimming roots and stems. Then store cured onions in a cool dark location with plenty of air circulation. Most long day reds will keep for 2-4 months if properly cured and stored.
With their beautiful color and zingy flavor, long day red onions make a delicious addition to any northern vegetable plot. Try growing a few of these top-rated varieties this season!
Choosing the Right VarietyWe have a number of instructional videos to share with you, and we are making more all the time! Check back often; these videos are designed to help you select the best onion variety for your area, as well as offer tips to help with planting, caring for, and harvesting your onion plants!
Though we grow great onion plants, our farm also has some of the best leeks and shallots on the market! Lancelot Leek Plants
Check out our brand-new All Natural Onion Growing Success Kit. It has everything you need to grow your best all-natural onion crop yet.
Introducing our new Onion Growing Success Kit to help you grow your most successful onion crop ever!
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Short Day or Long Day Onions? Choosing the Right Varieties, Harvesting & Storing
FAQ
Are red burgundy onions long day?
Is Sweet Spanish yellow Utah Jumbo onion long day or short day?
Which onions keep the longest?
What is a long day onion?
Long-day onions form bulbs when days reach 14 or more hours in length, so they’re best suited for growing in northern regions with longer days–USDA hardiness zones 6 and colder. Long-day onions tend to have a more pungent flavor and thicker skins due to the cooler temperatures, making these varieties generally better for storage than fresh eating.
How long does a long day sweet onion last?
Long day sweet and storage onion varieties do well in the northern states that have between 14-16 hours of daylight length. Long day sweet onion varieties generally mature a few weeks before long day storage onion varieties and will keep from one to four months, so eat them first.
What is the best long day onion?
Simply the best long day red onion grown in the Northern areas. Deep internal red color continues to develop during storage. May not do well in Southern portions on the long day areas since this is a true long day and does require at least 15 hours of daylength to bulb. Redwing onions are slightly more pungent than Red Zeppelin.
Do long day onions grow better?
Long Day onions grow better in the North where summer days are long. Usually zones 6 thru 3 are included in the Long Day onion group. Onions form bulbs in response to day length. Long-day onions need about 14 to 15 hours of daylight to bulb. Ailsa Craig Exhibition is a large onion that has a unique mildly sweet flavor!
Where do long-day onions grow?
Long-day onions thrive in areas where summer days are longer than 14 hours–in the Northern hemisphere, that’s Virginia to Northern California and above. The key with photoperiod-sensitive onions is to plan for the plants to reach their full vegetative capacity right as the natural daylight triggers them into the next stage of growth.
When should I eat long day sweet onion?
Long day sweet onion varieties generally mature a few weeks before long day storage onion varieties and will keep from one to four months, so eat them first. These varieties will do best from the Midwest to the Canadian border. If planted early, long day onion varieties will do well in the northern half of the intermediate day areas.