Gladstone

Family: Amaryllidaceae Vegetable

Planting Schedule

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Sweet, mellow Gladstone onions bloom with a clean, golden fragrance and a gently crisp bite that turns especially inviting when roasted or caramelized.

The bulbs mature in about 95 days to a handsome, globe-to-flat shape with warm, papery skins and a tender interior texture that holds its integrity for slicing, layering, and slow-simmered sauces. Grow Gladstone for reliable, market-ready bulbs that shine in fresh salads, savory roasts, and quick pickles alike.

Light: Full SunMaturity: 95 DaysHabit: Bulbing

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Gladstone 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 18th	Aug 21st – Aug 29th
Zone 2b	Mar 20th	May 8th	Aug 11th – Aug 25th
Zone 3a	Mar 20th	May 8th	Aug 11th – Sep 1st
Zone 3b	Mar 24th	May 12th	Aug 15th – Sep 21st
Zone 4a	Mar 20th	May 8th	Aug 11th – Sep 24th
Zone 4b	Mar 18th	May 6th	Aug 9th – Sep 27th
Zone 5a	Mar 13th	May 1st	Aug 4th – Sep 30th
Zone 5b	Mar 9th	Apr 27th	Jul 31st – Oct 5th
Zone 6a	Mar 6th	Apr 24th	Jul 28th – Oct 10th
Zone 6b	Feb 28th	Apr 18th	Jul 22nd – Oct 16th
Zone 7a	Feb 23rd	Apr 13th	Jul 17th – Oct 20th
Zone 7b	Feb 13th	Apr 3rd	Jul 7th – Oct 28th
Zone 8a	Feb 4th	Mar 25th	Jun 28th – Nov 5th
Zone 8b	Jan 26th	Mar 16th	Jun 19th – Nov 12th
Zone 9a	Jan 9th	Feb 27th	Jun 2nd – Nov 26th
Zone 9b	Dec 15th	Feb 2nd	May 8th – Dec 9th
Zone 10a	—	Oct 1st	Jan 4th – Feb 28th
Zone 10b	—	Oct 1st	Jan 4th – Feb 28th
Zone 11a	—	Oct 1st	Jan 4th – Feb 28th
Zone 11b	—	Oct 1st	Jan 4th – Feb 28th
Zone 12a	—	Oct 1st	Jan 4th – Feb 28th
Zone 12b	—	Oct 1st	Jan 4th – Feb 28th
Zone 13a	—	Oct 1st	Jan 4th – Feb 28th
Zone 13b	—	Oct 1st	Jan 4th – 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)	28
Harden Off (days)	7

Culinary Notes

Chef's Note

Gladstone is built for the transition from raw crunch to deep roast sweetness—its mellow, clean bite doesn’t overpower. Use it for caramelized layers or quick pickles where it keeps structure and stays pleasantly snappy.

Best Uses

roast wedges until lacquered and caramel-sweet
caramelize low and slow for jammy layers
quick-pickle thin slices for crisp tang
raw salad duty where you want mellow crunch instead of sharp sting

Flavor Profile

sweet and mellow gently crisp bite clean golden allium fragrance tender, slice-holding interior

Kitchen Pairings

balsamic vinegar goat cheese thyme butter beef broth sherry vinegar

Frequently Asked Questions

What pest or disease is most common on onion (Allium cepa), and what should I do if I see it?

Onions (Allium cepa) commonly get downy mildew (gray-violet growth on leaves) and botrytis/neck rot when plants stay wet. Remove and discard infected leaves or bulbs, improve airflow by thinning and spacing, and avoid overhead watering—water at the soil line. If you see repeated mildew pressure, use a labeled fungicide for onions and follow the product’s interval.

How often should I water onion bulbs during the main growing phase (mid-season)?

During the main bulb-filling phase, keep soil consistently moist but not soggy—aim for about 1 inch (2.5 cm) of water per week, split into 2–3 watering days during dry spells. Let the top few centimeters of soil dry slightly between waterings to prevent rot, especially as the bulbs start to enlarge. Stop regular watering 7–14 days before harvest so skins cure properly.

How can I tell when onion (Allium cepa) is ready to harvest?

Harvest when about half the tops have fallen over and the necks feel dry and tight, typically around 95 days from planting for this crop. Bulbs should have fully formed skins and a papery outer layer. Lift on a dry day, cure the onions in a warm, airy spot for 1–2 weeks, and store only after necks are fully dried.