Skip to product information
An image of the plant grown with seed for Ailsa Craig Onion Seeds - Heirloom Variety, Spanish Type, Sweet Large Straw Yellow Globes, Ideal for Burgers & Salads, Long Storing, Non-GMO
  • An image of the plant grown with seed for Ailsa Craig Onion Seeds - Heirloom Variety, Spanish Type, Sweet Large Straw Yellow Globes, Ideal for Burgers & Salads, Long Storing, Non-GMO
Ailsa Craig Onion Seeds - Heirloom Variety, Spanish Type, Sweet Large Straw Yellow Globes, Ideal for Burgers & Salads, Long Storing, Non-GMO
$4.99 CAD
Maturity

110 Days
Sunlight

Full Sun
Watering

Regular

Difficulty

Medium difficulty
Life cycle

Annual
Grow Zones

3 - 9

Quick Reference

Zones

Plant Hardiness Zones describe the average minimum winter temperature for a region. They tell you where a plant can reliably survive outdoors. For example, Zone 5 can handle colder winters than Zone 9. Matching a plant to your zone increases the chance of long-term success.

Days

  • For food crops: Days to maturity is the expected number of days from planting to first harvest. This helps gardeners plan their growing season and time their harvests.
  • For non-food plants: Days to germination indicates how long it usually takes seeds to sprout under normal conditions. This is key for starting seeds successfully.

Types

  • F1 (Hybrid): A cross between two parent varieties. Hybrids are bred for vigor, uniformity, and specific traits such as disease resistance. Seeds saved from F1 plants don’t grow true to type. That means if you try to regrow them from seed, the plant won't necessarily be the same as last year's
  • OP (Open-Pollinated): Varieties that naturally pollinate and remain stable across generations. Seeds can be saved and replanted with consistent results.
  • HM (Heirloom): An open-pollinated variety that has been handed down for many generations. Heirlooms are valued for flavor, tradition, and genetic diversity.

Grows

  • Outdoors: Well-suited for garden beds, raised beds, or open soil, where natural conditions are stable.
  • Windowsill: Compact plants that thrive in containers indoors, often needing only modest light.
  • Anywhere: Highly adaptable plants that perform reliably in both indoor and outdoor settings.

Lifecycle

  • Annual: Grows, flowers, sets seed, and dies in one growing season. Many vegetables and flowers are annuals.
  • Perennial: Lives for multiple years, regrowing each season after going dormant. Often used in landscaping or long-term food crops.
  • Sp. Perennial (Self-Perennializing): A plant that reseeds itself or self-pollinates, giving the effect of perennial growth even if individual plants live shorter lives.

Size

Indicates the recommended container size or soil depth for best growth.

  • “X″ Pot”: The ideal pot diameter (e.g., 5″ Pot), ensuring enough root space.
  • DS (Deep Soil): Requires planting directly in the ground or in a deep raised bed, as shallow pots restrict growth.
 More Details (Opens New Tab)
  • Distinctive Size and Taste: Produces large, straw-yellow globe onions weighing up to 1 kg (2 lbs) with a diameter of 15-20 cm (6-8 in), renowned for their sweetness and firm texture.
  • Optimal Growing Conditions: Thrives best as a long-day plant; requires full sun exposure and well-drained, fertile soil for optimum growth.
  • Harvesting and Storage: Ailsa Craig is a sweet Spanish type known for a longer storage capability than other varieties, making it an excellent choice for extended use.
  • Versatile Culinary Delights: These onions are perfect for enhancing the flavor of burgers, salads, and other dishes with their mild, sweet taste.
  • Robust Plant: Exhibits an increased resilience against common onion pests and diseases, ensuring a healthy growth and yield.

Discover the Ailsa Craig Onion, an English heirloom known for its impressive size and sweetness. These straw-yellow globes are perfect for enhancing your culinary creations, from salads to burgers. With a long storage capability, they provide a fresh taste for extended periods.

Ideal for long-day conditions, these onions thrive in full sun and well-drained soil. Start them indoors in March and transplant when the soil warms. Regular feeding ensures robust growth, making Ailsa Craig a must-have for any garden enthusiast looking to enjoy home-grown, sweet onions.
Size
How much seed do I need?

Seeds per gram: 250
Average germination rate: 85%

Package sizes

  • 75 seeds — 64 plants — covers about 32 sq. ft.
  • 1000 seeds — 850 plants — covers about 425 sq. ft.
  • 2000 seeds — 1700 plants — covers about 850 sq. ft.
  • 5000 seeds — 4250 plants — covers about 2,125 sq. ft.
  • 25000 seeds — 21250 plants — covers about 10,625 sq. ft.

Plant growth and coverage

  • Upright, clumping habit; long‑day Spanish type
  • Height: 45–60 cm (18–24 in)
  • Spread: 10–15 cm (4–6 in)
  • Spacing: 10–15 cm (4–6 in) between plants; 30–45 cm (12–18 in) between rows
  • Thrives in full sun with fertile, well‑drained soil; start indoors and transplant

Choosing a packet size

  • The 75-seed packet is ideal for home gardeners trialing Ailsa Craig, small beds, or a few tightly planted rows for fresh use.
  • The 1000-seed packet suits larger home gardens or community plots planning successions and plenty of bulbs for summer grilling and salads.
  • The 2000-seed packet fits small market growers or shared gardens aiming for a dedicated onion bed with consistent, uniform bulbs.
  • The 5000-seed packet is best for market growers planting multiple beds for steady farmers’ market supply.
  • The 25000-seed packet is geared to commercial and diversified farms planning field-scale production and storage inventory.
GROWING INSTRUCTIONS

Start Ailsa Craig Onion seeds indoors in mid to late March. Use soil packs or a seed flat, ensuring seedlings reach about 4 inches in height before transplanting. Choose a location with full sun and fertile, well-draining soil.

Germinate seeds indoors at a temperature of 65-75°F. Harden off seedlings by gradually exposing them to outdoor conditions over a week. Transplant when the soil is workable, spacing them 6 inches apart in rows 18 inches apart.

Water regularly and feed every two weeks with a balanced fertilizer and liquid seaweed. Harvest when bulbs are large and tops begin to fall over. Cure bulbs in a dry, ventilated area before storing to enjoy their sweet flavor for months.
SHIPPING & RETURNS

In Canada, we use fast shipping from our Canadian warehouses. You can expect delivery in 1-3 days.

In the USA, We use our US warehouses, and you can expect your order in 1-3 days, too.

No postaged lettermail or slow shipping from across the world. No customs fees or orders withheld at the border. Tracking numbers for all orders.

We strive to process and ship all orders in a timely manner, working diligently to ensure that your items are on their way to you as soon as possible. Our return policy covers you for late, damaged or defective products.

 Read Our Shipping & Returns Policy

You may also like