Cortland

Family: Amaryllidaceae Vegetable

Planting Schedule

Provide your location or planting zone to unlock dates and add Cortland to a garden.

Sweet, mellow, and richly aromatic, Cortland yellow onions form handsome bulbs with a warm golden-brown skin and a tender, juicy interior that tastes wonderfully balanced—never harsh.

The flesh stays crisp and succulent at harvest, making Cortland a standout for fresh slicing, caramelizing, and roasting, as well as for silky sauces and classic pickled preparations. Grow for a reliable 90-day rhythm and enjoy a harvest that turns everyday meals into something special with its gentle, sunny flavor.

Light: Full SunMaturity: 90 DaysHabit: Bulbing

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Cortland Planting Dates by USDA Zone

Estimated US hardiness-zone windows for sow, transplant, and harvest. Enter a US ZIP above for exact local dates, or open a zone below.

Zone	Start Indoors	Sow / Transplant	Harvest
Zone 1a	Protected Environment Only
Zone 1b	Protected Environment Only
Zone 2a	Mar 30th	May 25th	Aug 23rd – Aug 29th
Zone 2b	Mar 20th	May 15th	Aug 13th – Aug 25th
Zone 3a	Mar 20th	May 15th	Aug 13th – Sep 1st
Zone 3b	Mar 24th	May 19th	Aug 17th – Sep 21st
Zone 4a	Mar 20th	May 15th	Aug 13th – Sep 24th
Zone 4b	Mar 18th	May 13th	Aug 11th – Sep 27th
Zone 5a	Mar 13th	May 8th	Aug 6th – Sep 30th
Zone 5b	Mar 9th	May 4th	Aug 2nd – Oct 5th
Zone 6a	Mar 6th	May 1st	Jul 30th – Oct 10th
Zone 6b	Feb 28th	Apr 25th	Jul 24th – Oct 16th
Zone 7a	Feb 23rd	Apr 20th	Jul 19th – Oct 20th
Zone 7b	Feb 13th	Apr 10th	Jul 9th – Oct 28th
Zone 8a	Feb 4th	Apr 1st	Jun 30th – Nov 5th
Zone 8b	Jan 26th	Mar 23rd	Jun 21st – Nov 12th
Zone 9a	Jan 9th	Mar 6th	Jun 4th – Nov 26th
Zone 9b	Dec 15th	Feb 9th	May 10th – Dec 9th
Zone 10a	—	Oct 1st	Dec 30th – Feb 28th
Zone 10b	—	Oct 1st	Dec 30th – Feb 28th
Zone 11a	—	Oct 1st	Dec 30th – Feb 28th
Zone 11b	—	Oct 1st	Dec 30th – Feb 28th
Zone 12a	—	Oct 1st	Dec 30th – Feb 28th
Zone 12b	—	Oct 1st	Dec 30th – Feb 28th
Zone 13a	—	Oct 1st	Dec 30th – Feb 28th
Zone 13b	—	Oct 1st	Dec 30th – Feb 28th

Crop Details

Trait	Value
Days to Maturity	90
Sun Requirements	Full Sun
Growth Habit	Bulbing
Support Needed	None
Planting Depth	Normal
Germination Temp (°F)	75
Min Soil Temp (°F)	45
Min Night Temp (°F)	28
Harden Off (days)	7

Culinary Notes

Chef's Note

Cortland’s mellow sweetness and crisp, juicy texture make it behave well in the heat—caramelizes cleanly and roasts into jammy edges without that sharp, eye-watering bite. It’s also a rare yellow onion that can stand up raw in slices because the flavor stays sunny and rounded instead of biting.

Best Uses

raw or lightly dressed slicing for burger stacks and salad crunch
caramelizing until deeply golden without turning aggressively pungent
roasting for jammy edges and sweet, soft centers
silky-cooked sauces (fondant-style reductions) that stay smooth

Flavor Profile

sweet, mellow onion aromatics crisp-tender juicy bite balanced, never harsh finish

Kitchen Pairings

butter thyme aged cheddar brie balsamic vinegar beef

Frequently Asked Questions

What pest or disease issue most commonly affects Allium cepa (Cortland onion), and how do I treat it?

Onions (Allium cepa) are especially prone to fungal downy mildew and botrytis/neck rot during cool, humid weather. Remove any infected foliage immediately, improve airflow by spacing plants and avoiding overhead watering, and water at the base in the morning so leaves dry quickly. If problems persist, use a labeled fungicide effective for downy mildew/neck rot on onions and follow the label for intervals and application timing.

How often should I water Cortland onions during the main growing phase?

During active bulbing (once the plants are established), keep soil consistently moist but not waterlogged—aim for roughly 1 inch (2.5 cm) of water per week, split into 1–2 waterings depending on heat. Check moisture by feel: the top 1 inch should be moist, not soggy, and stop short of pooling to prevent rot. When bulbs begin to size up, you can taper slightly to avoid excess moisture that encourages neck rot.

How can I tell when Cortland onions are ready to harvest?

Harvest when about 50–75% of tops have fallen over and the remaining foliage is starting to yellow, typically around 90 days for Allium cepa. Gently lift a bulb: the skin should be papery and tight, not wet or peeling easily. Harvest on a dry day and leave bulbs on the surface to cure briefly before moving them to a warm, airy spot for proper drying.