Yellow Sweet Spanish, Onion Seeds

Yellow Sweet Spanish Onion Seed

Generous golden globes commonly reach four to six inches
Long-day growth fits northern onion gardens
Mild, sweet flesh adapts easily across recipes
Well-cured bulbs provide dependable storage after harvest

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Key Attributes

Botanical Name

Allium cepa

Days to maturity

110 Days

Sun

Full Sun

Packet

250 Seeds

About Yellow Sweet Spanish, Onion Seed, Onion Seed

Yellow Sweet Spanish onion seeds grow into a classic heirloom variety that dates back to the early 20th century, prized for its large, globe-shaped bulbs and mild, sweet flavor. These onions typically reach 4–6 inches in diameter and feature golden-yellow skin with crisp, white flesh inside. They thrive in full sun and loose, well-drained soil rich in organic matter, requiring consistent moisture and a long growing season of about 110 days.

Growing details

Planting

Sow Depth

1/8"

Days to Germination

7–14 days

In-row plant spacing

3-4"

Row Spacing

12-18"

Plant profile

Maturity

Summer

Life Cycle

Annual

Plant Height

24 inches

Growth Habits

Clumping, Upright

Type

FULL SIZE ONIONS

Seed & variety

Seeds Per Ounce

8,000

Color

Yellow

Seed Type

Heirloom

Growing Season

Cool-Season Crop

Before Planting

For Onion, select a full-sun location with fertile, loose, well-drained soil. Incorporate compost and use a soil test to correct phosphorus, potassium, and pH while avoiding fresh manure. Select the correct short-, intermediate-, or long-day type for your latitude, and prepare a smooth, weed-free bed before sowing or setting transplants.

Planting

Start onion seed indoors 10–12 weeks before the last spring frost, or direct sow as soon as the soil can be worked. Give indoor seedlings strong light and steady moisture, harden them gradually, and transplant while weather is cool. Thin bulb onions to 3–4 inches apart.

Watering

Provide about 1 inch of water weekly, keeping moisture steady while bulbs enlarge. Water at soil level and avoid saturation; reduce and then stop irrigation as tops naturally fall and bulbs approach maturity.

Fertilizer

Apply nitrogen in light side-dressings during early leaf growth, following soil-test recommendations. Stop feeding once bulbs begin enlarging; late nitrogen delays maturity and reduces storage quality.

Harvesting

Harvest onions when most tops naturally yellow and fall. Lift bulbs gently rather than pulling, then cure them in a warm, dry, ventilated place until necks and outer skins are fully dry.

Tips

Keep beds weed-free because onions compete poorly. Gently expose bulb shoulders as they enlarge rather than hilling soil around them, and select the proper day-length type for your latitude.

AVG. Seeding Rate

1 oz./25', 1M/50', 5M/250', 25M/1,250', 580M/acre at 20 seeds/ft., in rows 18" apart.

Pests & Diseases

Onion seed can introduce Botrytis neck rot, downy mildew, purple blotch, and bacterial diseases; damping-off threatens young seedlings. Purchase tested seed, use sanitized trays, and avoid overly dense sowing. Rotate alliums, keep leaves dry, and discard seedlings with basal softening, water-soaked lesions, or abnormal twisting.

Onion thrips, onion maggots, leafminers, and cutworms are common. Rotate allium crops, use insect netting early, remove cull bulbs and residue, and inspect folded leaves for feeding damage.