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Ailsa Craig

Onion
Zone 1a Save Garden

Planting Schedule

Add Ailsa Craig to your garden to build a schedule and get reminders.
Botanical illustration of Ailsa Craig
95d to harvest

Sweet, golden bulbs with a gentle bite—Ailsa Craig brings a luminous, honeyed flavor and a beautifully crisp yet tender texture to the garden. The classic Yellow Onion form develops firm, well-filled layers that roast to a melting softness and shine in fresh salads, slow-simmered sauces, and quick pickling for a bright, balanced tang. Grow it for reliable, home-garden performance and that unmistakably refined “Ailsa” sweetness at harvest.

Crop Dates

Growing note: Zone 1a has only 30 frost-free days — shorter than this crop's 95-day maturity. Outdoor planting is not viable; use protected cultivation.
MilestoneDate
Last FrostJun 15th
Growing ApproachProtected Environment Only

Crop Details

TraitValue
Days to Maturity95
Sun RequirementsFull SunFull sun
Growth HabitBulbing
Support NeededNone
Planting DepthNormal
Germination Temp (°F)70
Min Soil Temp (°F)45
Min Night Temp (°F)35
Harden Off (days)Not Required

Today's Conditions

Outdoor planting for Ailsa Craig in Zone 1a typically begins around Indoor Lights Only. Wait until soil reaches at least 45°F before transplanting Ailsa Craig.

Garden Alerts

Zone 1a has only 30 frost-free days — shorter than this crop's 95-day maturity. Outdoor planting is not viable; use protected cultivation.

Recommended Companions

Parisian Carrot
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Early Flat Dutch Cabbage
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Summer Bibb Lettuce
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Red Little Gem Lettuce
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Early Jersey Wakefield Cabbage
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Touchon Carrot
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Frequently Asked Questions

Ailsa Craig tomato plants keep getting brown, concentric rings on lower leaves—what disease is it and how do I stop it?
Brown concentric rings on older, lower leaves of Ailsa Craig tomatoes are classic for early blight (Alternaria). Remove and destroy infected leaves immediately, then spray with a labeled fungicide for tomato early blight and repeat according to the label (especially after rain/dew). Keep foliage as dry as possible by watering at the soil line and spacing plants so air moves through the canopy.
When is Ailsa Craig ready to harvest, and what signs should I look for?
Harvest when fruits are fully colored (a deep, uniform red) and reach their typical large “heirloom” size—Ailsa Craig usually matures in about 95 days. Pick fruits when they come off the vine with a gentle twist and the skin is firm but gives slightly under light pressure. If frost threatens, harvest even slightly less-red fruit and let them ripen indoors at warm room temperature.
Botanical illustration of Ailsa Craig

Sweet, golden bulbs with a gentle bite—Ailsa Craig brings a luminous, honeyed flavor and a beautifully crisp yet tender texture to the garden. The classic Yellow Onion form develops firm, well-filled layers that roast to a melting softness and shine in fresh salads, slow-simmered sauces, and quick pickling for a bright, balanced tang. Grow it for reliable, home-garden performance and that unmistakably refined “Ailsa” sweetness at harvest.

Today's Conditions

Outdoor planting for Ailsa Craig in Zone 1a typically begins around Indoor Lights Only. Wait until soil reaches at least 45°F before transplanting Ailsa Craig.

Garden Alerts

Zone 1a has only 30 frost-free days — shorter than this crop's 95-day maturity. Outdoor planting is not viable; use protected cultivation.

Sowing Tips

Soil Temperature

Direct sow or transplant when soil at planting depth holds 45°F for reliable germination and early growth.

Expert Note

Start with clean, well-drained soil and transplant into consistently cool conditions; Ailsa Craig performs best when it has steady growth before bulbing and is harvested before extended wet fall weather reduces shelf life.