Red Amposta

Family: Amaryllidaceae Vegetable

Planting Schedule

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Rich, wine-red skins glow with a satin sheen, opening to a sweet, mellow interior that’s tender rather than sharp—ideal for gardeners who want bold color with gentle flavor.

Red Amposta forms well-filled bulbs with a classic globe shape and crisp, layered texture that holds up beautifully for roasting, caramelizing, and slow-simmered sauces. Grow it for standout fresh slices and vibrant pickling results, when its color turns especially jewel-like.

Light: Full SunMaturity: 95 DaysHabit: Bulbing

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Red Amposta 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 16th	May 25th	Aug 28th – Aug 29th
Zone 2b	Mar 6th	May 15th	Aug 18th – Aug 25th
Zone 3a	Mar 6th	May 15th	Aug 18th – Sep 1st
Zone 3b	Mar 10th	May 19th	Aug 22nd – Sep 21st
Zone 4a	Mar 6th	May 15th	Aug 18th – Sep 24th
Zone 4b	Mar 4th	May 13th	Aug 16th – Sep 27th
Zone 5a	Feb 27th	May 8th	Aug 11th – Sep 30th
Zone 5b	Feb 23rd	May 4th	Aug 7th – Oct 5th
Zone 6a	Feb 20th	May 1st	Aug 4th – Oct 10th
Zone 6b	Feb 14th	Apr 25th	Jul 29th – Oct 16th
Zone 7a	Feb 9th	Apr 20th	Jul 24th – Oct 20th
Zone 7b	Jan 30th	Apr 10th	Jul 14th – Oct 28th
Zone 8a	Jan 21st	Apr 1st	Jul 5th – Nov 5th
Zone 8b	Jan 12th	Mar 23rd	Jun 26th – Nov 12th
Zone 9a	Dec 26th	Mar 6th	Jun 9th – Nov 26th
Zone 9b	Dec 1st	Feb 9th	May 15th – Dec 9th
Zone 10a	Continuous Production
Zone 10b	Continuous Production
Zone 11a	Continuous Production
Zone 11b	Continuous Production
Zone 12a	Continuous Production
Zone 12b	Continuous Production
Zone 13a	Continuous Production
Zone 13b	Continuous Production

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)	7

Culinary Notes

Chef's Note

Red Amposta is bred for color and gentleness: the interior stays tender and layered, so it won’t blast your palate like sharper red onions. Use it thick—roast, caramelize, or pickle—to let the wine-red sugars go glossy and sweet, while the slices keep a satisfying bite.

Best Uses

thick raw slices on sandwiches where they stay crisp instead of biting
roasted wedges that caramelize into jammy edges
caramelizing for a glossy, deep-red base for braises
quick pickling for jewel-toned crunch

Flavor Profile

sweet, mellow onion flavor tender, layered crispness wine-red pigments that deepen when cooked turns silky when slow-cooked

Kitchen Pairings

balsamic vinegar goat cheese beef or lamb thyme aged cheddar butter

Frequently Asked Questions

What pest or disease problem commonly affects Allium cepa (red onions like Red Amposta), and how can I control it?

Onions (Allium cepa) commonly suffer from purple blotch (Alternaria porri) and other leaf blights that show as purple-brown spots on foliage. Improve airflow by spacing plants properly, water at the base (not on leaves), and remove badly spotted leaves; if outbreaks persist, apply a labeled fungicide intended for onions/leaf blights following the product’s schedule. Avoid replanting onions in the same bed in consecutive seasons to reduce carryover of fungal spores.

How often should I water Allium cepa during the main growing phase, and what soil moisture level is ideal?

During active bulb growth, keep the soil consistently moist but not soggy—aim for roughly 1 inch (2.5 cm) of water per week, adjusted for rainfall and your soil’s drainage. Water deeply when the top 1–2 inches (2.5–5 cm) of soil dry out, because onions need steady moisture to form well-sized bulbs. Once bulbs start swelling and the plants are about mid-season, reduce watering gradually to help the necks dry and prevent bulb rot.

How can I tell when Red Amposta onions are ready to harvest?

Harvest when about 50–70% of the tops have fallen over and the necks feel dry and constricted, typically around 95 days for Red Amposta. Stop watering about 1–2 weeks before harvest to encourage curing-ready tops. Lift gently (don’t yank) and cure the bulbs in a dry, airy place with good ventilation until the outer skins are papery and the necks are tightly sealed.