Green Bunching Onions

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Pest management: Onions and Garlic

The Basics

Green onions, also called bunching onions or scallions, grow easily from seed or transplants. Most green onions sold in grocery stores are simply bulbing onions (Allium cepa), picked while young, long before they form a bulb. But there is also Welsh onion/Japanese bunching onion (Allium fistulosum), which never forms a bulb and can be grown as a perennial clump.

When to plant

• Direct seed or transplant March through October, 2–3 inches apart
• To ensure a continuous supply of young, tender scallions, start small patches in succession every 3–4 weeks 
• For transplants, seed densely in pots about 5 weeks in advance
• Mature Allium fistulosum clumps can be dug up and divided

Harvest window

• Harvest throughout the season, about 60–80 days after planting
• If planted densely, harvest every other one to thin them
• Fall planted scallions may hold through the winter, but may bolt (send up a flower stalk) when the weather warms in early spring

Care overview

• Onions have shallow roots, so be sure to keep them evenly moist. A good layer of mulch will help keep the soil moist

Recommended Varieties for Santa Clara County^*

Southport White Globe, White Lisbon, White Sweet Spanish

^* Many other varieties may also do well here in Santa Clara County. This list is based on UC Master Gardener trials, taste tests, and feedback from local growers.