Onion Long Day Spanish Sweet Yellow produces large, round bulbs with pale yellow skins and crisp, juicy white flesh. Its mild, sweet flavor is delicious fresh, roasted or slowly caramelized. This non-GMO heirloom is a long-day onion, best suited to northern growing regions where long summer days support bulb development. Expect approximately 100–120 days to maturity from transplant under favorable conditions.

Germination Rate: 85%. Test Date: 4/26. OSI

Texas Minimum Germination Rate: 70%

Why Choose Onion Long Day Spanish Sweet Yellow?

• Heirloom Variety: Grow a classic sweet yellow onion for your home kitchen.
• Non-GMO Seeds: A dependable choice for gardeners seeking non-GMO varieties.
• Large, Juicy Bulbs: White flesh and mild flavor make these onions useful raw or cooked.
• Long-Day Variety: Choose this onion for regions with approximately 14–16 hours of summer daylight at bulbing.
• Kitchen Versatility: Slice for sandwiches, roast in wedges or caramelize for a savory topping.

Planting Tips for Success

• When to Plant: Start indoors 8–10 weeks before your last spring frost, then transplant in early spring as local conditions allow. Long-day onions are not the usual choice for southern Texas bulb production.
• Sunlight: Plant in full sun with at least 6–8 hours of direct light daily. Day length, not just direct sunshine, controls bulbing.
• Soil: Use fertile, well-draining soil with a pH of 6.0–7.0 and incorporate finished compost before planting.
• Depth and Spacing: Sow seeds ¼ inch deep. Thin or space transplants 4–6 inches apart in rows 12–18 inches apart.
• Watering: Keep soil evenly moist without waterlogging. Reduce watering as bulbs mature and tops naturally fall.
• Support: No staking is needed.
• Fertilizing: Feed during early leafy growth according to your fertilizer label and soil needs. Stop nitrogen feeding when bulbs begin to swell.
• Maturity: Approximately 100–120 days from transplant, depending on growing conditions.
• Harvest and Storage: Harvest when tops fall and begin to dry. Cure in a dry, shaded, well-ventilated location until necks and outer skins are dry. Store sound bulbs in a cool, dry place and check regularly.

Why Choose David's Garden Seeds®?

• Veteran-Owned: Supplying premium seeds since 2009.
• GO TEXAN Certified: Supporting local agriculture and communities.
• Integrity Pledge: David's Garden Seeds has taken the Seed Integrity Pledge.
• Vegetable Seed License: David's Garden Seeds has been granted a Vegetable Seed License for the State of Texas.

Cooking Methods

• Fresh: Thinly slice harvested onions for sandwiches, salads or salsa.
• Caramelized: Cook slowly in butter or olive oil until deeply golden for burgers, flatbreads or pasta.
• Roasted: Roast thick wedges until tender and browned at the edges.
• Soups and Stews: Add chopped onion as a flavorful base for broth, sauces or hearty soups.

Order Spanish Sweet Yellow Onion Seeds Today

Grow your own sweet yellow onions for fresh garden-to-table meals.

Nutritional Information

Approximate values per 1 medium harvested onion (110 g), raw. These values describe the onion, not the seeds.

• Calories: 44
• Total Fat: 0.1 g (0% Daily Value)
• Sodium: 4 mg (0% Daily Value)
• Total Carbohydrates: 10.3 g (4% Daily Value)
• Dietary Fiber: 1.9 g (7% Daily Value)
• Total Sugars: 4.7 g
• Protein: 1.2 g
• Vitamin C: 7.4 mg (8% Daily Value)
• Potassium: 161 mg (3% Daily Value)

Important Disclosures

• Variety Disclaimer: Seed variety, packet size and count are as described. Results vary with climate, soil and gardening practices.
• Seed Storage: Store seeds in a cool, dry place away from direct sunlight.
• Planting Zones: Grow as a cool-season annual where local planting conditions are suitable. For bulb production, matching this long-day variety to your region's summer day length matters more than hardiness zone alone.

Recipe: Garlic-Herb Roasted Spanish Sweet Yellow Onions

Use harvested Spanish Sweet Yellow onions from your garden, not the seeds in this packet. Roasting brings out their sweetness and gives the edges a savory golden finish.

Serves: 4. Prep: 10 minutes. Cook: 35–45 minutes.

Ingredients

• 3 medium to large harvested Spanish Sweet Yellow onions, about 1½ pounds
• 2 tablespoons olive oil
• 2 garlic cloves, finely minced
• 1 teaspoon dried thyme or 1 tablespoon fresh thyme leaves
• ½ teaspoon salt, or to taste
• ¼ teaspoon black pepper
• 1 tablespoon balsamic vinegar, optional
• 1 tablespoon chopped fresh parsley, optional

Directions

1. Heat the oven to 400°F. Line a rimmed baking sheet with parchment paper.
2. Rinse the onions before peeling. Trim the dry ends, peel and cut each onion into 6–8 wedges, leaving a little root end attached to hold the layers together.
3. Toss the wedges with olive oil, garlic, thyme, salt and pepper. Spread in a single layer with a cut side against the pan.
4. Roast for 35–45 minutes, turning carefully halfway through, until tender and golden at the edges.
5. If using balsamic vinegar, drizzle it over the onions during the final 5 minutes of roasting. Finish with parsley and serve warm.

Serving Ideas: Serve beside chicken or beans, spoon onto toasted bread or add to a grain bowl. For a simpler version, omit the balsamic vinegar and finish with a squeeze of lemon.

Storage: Refrigerate leftovers in a covered container within 2 hours and use within 3–4 days. Reheat until steaming hot.

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