Green onions. Bunching onions. Scallions. These are all names for the same thing in most people's minds: undersized onions, generally eaten raw. At home we use the straight white shank (usually bulbless) and as much of the upper green portion as is tender and mild. In the supermarkets, scallions often come trimmed and bundled, a dozen or so to the bunch, bound by rubber bands. But to get the very best scallions for eating raw in salads, garnishes or solo, you'll want to grow them yourself.
A lot of people think that scallions are simply onions pulled before they are mature. But while such onions may look like a scallion, they may not match the taste of one. Good scallions must be mild enough to be enjoyable raw, without the eye-watering pungency of many onions. Just any old onion won't do.
A handful of ordinary onions dominate commercial scallion production, most of which occurs in the South and increasingly in Mexico. In the South, any long-day onion (requiring daylengths of 14 to 16 hours to form bulbs) will fail to make a large bulb and will instead become a smooth, straight-sided scallion. Unfortunately, any major contender as a commercial scallion must also be available as cheap seed. That's why more than half the scallions brought to winter market are 'Southport White Globe'. It produces abundant seed but has a powerful pungent bite -- not a great scallion.
There are, however, a few mild-flavored long-day onion varieties traditionally grown for scallions during the cool months. 'White Lisbon' and 'Sweet Spanish Valencia' are two good ones. If you buy sweet, mild scallions in the winter supermarket, they're likely to be one of these varieties or a close relative.
Any of the short-day sweet onions (12 to 14 hours of daylight) like 'Granex', 'Grano 1015', 'Bermuda' or 'Crystal Wax' -- though their seed is too expensive for market growers -- make excellent scallions wherever they are winter-hardy. Plant them in late summer (the same time you would plant a bulb onion) and begin harvesting the thinnings as soon as they reach pencil size. Farther north, into zone 6, try 'Walla Walla', planting it in late summer to overwinter.
Late in the season, the short-day onions will begin to bulb up. But you can keep pulling them for use in salads as long as you like. There is a growing market for undersized 'Grano 1015' (a.k.a. ' Texas Sweetie ' or 'Vidalia') harvested green at the 11/2- to 2-inch size and sold in small bunches with the green stem and leaves.
Leonard Pike, a sweet onion breeder at Texas A&M, told me recently that he was surprised how good these undersized onions are. He expected that mature onions would be milder, but when he ran tests, he found that the age of the onions had no effect on pungency. He also said that he was surprised how far north some growers were producing respectable 'Grano 1015's, even into Nebraska and Missouri. If northerners are interested in growing green onions, it doesn't matter that short-day sweet onions don't reach full size. Plant either seed or mail-order transplants. Pull the green onions in late spring and early summer.
In the Orient, where Allium fistulosum has been cultivated for centuries, there are many variants. Not all of them look like scallions, and some are very pungent. But in the United States' seed catalogs we see only nebuka or he-shi-ko types, which make excellent mild scallions. About half the scallion offerings in any catalog will be a Japanese bunching onion. They are also known as Welsh onions, from the German word welsch -- foreign or southern. Another synonym is ciboule.
Bunching onions grow well in the North and the South. Winter hardiness varies among varieties, however, and is clearly noted in most catalogs. If a variety is winter hardy in your area, the plants can become perennial, which is an excellent way to grow them.
Plant seed anytime from early spring through summer. Begin scallions about 10 weeks later, when the onions reach pencil size. To perennialize the harvest, thin or transplant seedlings to four inches apart. Begin harvesting side shoots in two to four months. You may need to rejuvenate your bed every five years or so with a new sowing or by transplanting side shoots.
There are a handful of scallion varieties that are crosses between (Allium fistulosum) of the nebuka type and mild varieties of ordinary onions, like Bermuda. Even though these hybrids have settled down enough to behave like open-pollinated plants, and thus simplify seed production, their seed is still too expensive for commercial scallion growers. They are excellent for gardeners, however.
One of the best of these is 'Beltsville Bunching', which is both winter-hardy and one of the most heat-tolerant. A mature bed of 'Beltsville Bunching' will provide excellent scallions nearly year-round. Though some of these will be much larger than pencil-sized, their flavor will still be sweet and mild.
Not all hybrids of (A. cepa and A. fistulosum) are scallions. (A. fistulosum) is virtually immune to pink root rot and has been widely used by breeders to introduce disease resistance into ordinary onions. It has also been used to create several shallot varieties.
Botanists used to think that the Egyptian, or topset, onion was a strain of the ordinary onion. Recent DNA testing has shown that it is actually a very old natural cross between (A. fistulosum and A. cepa). Though Egyptian onions do not bulb and are often called scallions, they are extremely hot and don't compare well with Japanese bunching onions or commercial scallions.
The outer skins are usually rather tough, which is why some people call them "peelers." Most strains have reddish shanks. But there are a couple of white varieties. 'McCullar's White' is one that is said to be less pungent than most. The mildest part of Egyptian onions is the tips of the young leaves that emerge from the ground in late winter.
If your definition of scallion is any small green onion, with little or no bulb, then almost any kind of onion you plant can be harvested early in the season for scallions. But most people think that scallions should be sweet and mild. Here are several strategies for growing the best scallions ever.
From seed: This is the best way for most gardeners. In the South any sweet onion variety will work well. Plant short-day types in late summer or fall and thin for scallions. Plant long-day types either in spring or fall. In the North, plant Japanese bunching onion varieties in late summer or spring.
From transplants: Many seed companies sell southern-grown sweet onion transplants through the mail. North or south, plant transplants an inch apart and begin harvesting when they are scallion-sized. In the north, short-day varieties will bulb up in late spring and early summer: Disappointing onions but fine scallions!
From divisions: Many Japanese bunching onion varieties will perennialize. Get divisions from a neighbor or, after starting your own from seed and harvesting scallions until plants are about 6 inches apart, let the plants mature and harvest side shoots as they form. Rejuvenate perennial bunching onion beds from seed every five years or as needed.
From onion sets or "top sets": This is not a good way to grow good scallions. Onion sets are keeper-type onions. The compounds that let them keep well also make them very hot -- great for cooking but not good as scallions. Likewise, most Egyptian or topset onions are extremely hot.