Green onions have been cultivated for centuries in various forms and are produced around the world. China is a significant producer and the United States ranks in the global top ten. Domestically, California leads production, with a handful of other states including Arizona, Georgia, Texas, and the Pacific Northwest contributing to annual supply. Imports from Mexico continue to rise to meet demand, especially during the U.S. off season.
Green onions are often referred to as bunched or spring onions, salad onions, or scallions. Each refers to a densely planted, mild flavored, immature bulb onion of the common Allium cepa species.
Many of today’s cultivars are hybrids of Allium cepa and Allium fistulosum (a Japanese bunching onion), which can produce either bulb or nonbulb plants. Day-length (short-day or long-day varieties dependent on hours of sunlight) influence growth characteristics, such as bulb development and size.
Varieties vary greatly, but White Lisbon is widely grown; Crystal Wax, Ebenezer, Eclipse, Hishiko, Ishikura, Kincho, Sweet Spanish, Tokyo Long, White Globe, and White Portugal are among the many other varieties available for growers depending on region and market specifications.
Green onions should be planted in mild climates with well-drained loamy soil and require regular irrigation during development. Due to shallow roots, plants are unable to compete with weeds, which will put young plants at risk. Plants are also vulnerable to wind and hail damage, as well as cold temperatures.
Once onions reach from a quarter- to half an inch in diameter and tops reach 6 to 8 inches in height, harvest begins by hand. Green onions are gathered and banded into bunches. Due to high perishability, bunches should be cooled immediately. Tops are generally trimmed to market specifications.