Ailsa Craig

Onion

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: In frost-free Zone 12b, grow this cool-season crop during the cooler dry season (October–February).

Milestone	Date
Start Indoors	—
Climate	Frost-Free Climate
Transplant / Sow Outdoors	Oct 1st
Harvest Begins	Jan 4th
Harvest Ends	Feb 28th

Crop Details

Trait	Value
Days to Maturity	95
Sun Requirements	Full Sun
Growth Habit	Bulbing
Support Needed	None
Planting Depth	Normal
Germination Temp (°F)	70
Min Soil Temp (°F)	45
Min Night Temp (°F)	35
Harden Off (days)	Not Required

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.

How often should I water Ailsa Craig tomatoes during the main growing phase to avoid fruit cracking and blossom-end rot?

During active flowering and fruit set, water deeply enough to moisten the root zone, typically every 2–3 days in warm weather, but only when the top 1 inch of soil feels dry. Aim for steady moisture—don’t let the soil swing from very dry to fully soaked, which can trigger cracking. Use a soaker hose or drip and keep water off leaves; mulch helps maintain even moisture around the plants.

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.