Garden Help > Vegetables

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. There is also Welsh onion/Japanese bunching onion (Allium fistulosum), which never forms a bulb and can be grown as a perennial clump.

Planting

• Direct seed or transplant 2 to 3 inches apart in March through October.
• To ensure a continuous supply of young, tender scallions, start small patches in succession every 3 to 4 weeks.
• If growing your own seedlings, seed densely in pots about 5 weeks before you want to plant, then separate them out as you transplant.
• Mature Allium fistulosum clumps can be dug up and divided.
• Onions have shallow roots, so be sure to keep them evenly moist. A good layer of mulch will help keep the soil moist.

Harvesting

• Harvest throughout the season, about 60 to 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.

Pest management

Onions and Garlic, UC IPM

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.