Sweet Onion

Sweet onions are mild bulb cultivars, not a separate day-length class. Many keep less well than pungent storage onions.

Sun

Full sun

Water

Even moisture

Spacing

6 in

First harvest

90–150 days from transplant; day-length and season dependent

Tips

• Match day-length response to latitude.
• Space 5–6 inches for large bulbs.
• Maintain moisture during bulb growth.
• Use damaged bulbs first and plan for shorter storage.
• Start seed indoors 8-12 weeks before planting out, then set seedlings about 1 inch deep and 4 inches apart.
• Keep shallow roots evenly moist with about 1 inch of water weekly and weed gently by hand.
• Do not mound soil over swelling bulbs or bend the tops down to hasten maturity.
• Watch for silvery leaf streaks and tiny thrips in leaf folds, and remove volunteer onions that harbor pests.
• Stop watering when most tops fall naturally, then lift and cure storage varieties in a dry, airy place.

Select local planting dates and short-, intermediate- or long-day seed for your latitude.

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