Red Cipollini Onion Seeds

Red Cipollini Onions — The Flat, Sweet Italian Onion Worth Every Extra Effort

Cipollini (pronounced chee-po-LEE-nee) are a traditional Italian onion type named for their distinctive shape — flat and disc-like rather than globe-shaped, typically 4–6 cm in diameter. Red cipollini have deep burgundy-purple skin and rings of pale pink to white flesh inside. They’re prized in Italian cooking for two qualities: their naturally high sugar content (even higher than standard sweet onions) and their shape, which allows them to caramelize completely and evenly when roasted whole. A pan of roasted whole cipollini — golden, sweet, slightly jammy, still holding their shape — is one of the most elegant and effortless preparations in the Italian kitchen.

Growing cipollini in Canada requires the same care as any long-day onion: a very early indoor start, consistent nitrogen feeding through early summer, and patience. The flat bulbs are unmistakable at harvest — unlike any other onion in the garden — and they store moderately well for 2–4 months. For Canadian gardeners who want to grow something genuinely different and impressive, red cipollini deliver at every stage: beautiful in the garden, stunning at harvest, and outstanding on the plate.

Starting Red Cipollini from Seed

Start seeds indoors 8–10 weeks before your last frost date — January to February in most Canadian regions. Sow ¼ inch deep at 15–21°C (60–70°F) and thin seedlings once they reach 10 cm tall to prevent competition. Trim tops to 5 cm to encourage stockier stems. Transplant outdoors 4–6 weeks before last frost, spacing 8–10 cm (3–4 in) apart — cipollini’s flat shape means they can be planted slightly more densely than globe types. Apply a nitrogen-rich fertilizer through early summer to maximize leaf growth before bulbing.

For the full process from sowing to cured bulb — including day-length selection, transplanting, and curing for storage — see our complete guide to growing onions from seed.

Soil, Care, and Watering

Cipollini need the same conditions as all onions: loose, well-draining, fertile soil with consistent moisture and good weed control. The flat shape means they develop at or very near the soil surface — don’t plant deeply. Keep consistently moist through early summer when leaf growth is building; taper watering as tops begin to yellow. Weeding is critical — cipollini’s shallow roots and flat shape make them particularly vulnerable to being crowded out.

Harvesting and Storage

Harvest when tops have fallen naturally and begun to brown — typically mid-to-late summer. The flat shape and burgundy skin are unmistakable. Cure in a warm, dry, ventilated location for 1–2 weeks. Red cipollini stores for 2–4 months in cool, dry conditions — longer than sweet onions but shorter than pungent yellow types. Their distinctive appearance and concentrated sweetness makes them worth growing in quantity for roasting through fall and early winter.

In the Kitchen

The signature preparation is whole roasted cipollini: peel (blanching briefly in boiling water loosens the skin), halve or leave whole, toss with olive oil and salt, and roast at 200°C (400°F) until golden and caramelized — about 30–40 minutes. The flat shape means they caramelize evenly on both faces without rolling around. Agrodolce (sweet-and-sour) cipollini is another classic: braise peeled whole onions in a mixture of balsamic vinegar, sugar, and butter until deeply glazed. Serve as a side dish or antipasto. Red cipollini also pickle beautifully — their small size, flat shape, and mild flavour make them ideal for quick or long-fermented pickles.

Saving Seeds from Red Cipollini Onions

Select the flattest, most true-to-type bulbs and overwinter for second-year flowering. Onion seed viability is short — 1–2 years maximum. Isolate from other Allium cepa varieties by 300+ metres for pure seed. The distinctive flat shape of cipollini is a specific trait that requires selection pressure over generations to maintain — choose seed-saving bulbs from the flattest plants each year.