By Jill Henderson
Of all the vegetables, herbs and spices that are used to season food and heal the body, the unassuming onion is rarely given its proper due. For a plant that serves so many needs and desires in our kitchens, gardens and herbal pantries, the savory spicy-sweet goodness of onions in all their forms should be elevated.
Onions and all of their onion-like relatives have long been classified as belonging to the Lilly (Lilliaceae) family, but in 2009 botanists began using a scientific system known as phylogenetics to reorganize many plant families based on genetic testing.
The entire Allium genus was reclassified as being a part of the Amaryllis (Amaryllidaceae) family of plants, which includes the lovely and highly regarded flowering perennials of the same name. Even so, botanists are still studying and debating the order of the genera Allium, which contains 15 subgenera and nearly 1,000 species!
Obviously, the most well-known onion is the common bulb onion, known to us botanical nuts as Allium cepa. Botanically speaking, cepa onions are all the same. The only comparable differences are in their shapes, colors and sizes, the day-length needed to grow them and their flavor and storability. In general, cepa onions are most often categorized as “cooking,” “sweet” or “storage” types.
Yellow onions are generally referred to as cooking, storage, or winter onions because they hold up well during long periods of cooking and are excellent keepers. Next are the red salad onions, which are sweet and mild-flavored, making them the best choice when raw onions are desired. Lastly, there are the white onions, which tend to be a bit smaller than their red or yellow counterparts. White onions are sweet, very mild and do not store well. While they are really best for fresh eating, people who don’t particularly like onions tend to gravitate toward them for cooking, as well.
If you like onions but can’t grow them due to climate or soil conditions, or because you don’t have the space, you might want to consider one of A. cepa’s perennial cousins such as bunching onions or scallions (Allium fistulosum), potato or multiplier onions (Allium cepa aggregatum) and walking onions (Allium cepa proliferum). All of these onions are true perennials that come back year after year from a single planting to produce dense clumps of elongated fleshy stems and copious leaves and, in the case of walking and potato onions, small bulbs that readily divide.
Walk Those Onions
One of my personal favorites is the walking, or Egyptian walking onion. Some people also refer to them as tree- or top-setting onions. Walking onions reproduce vegetatively, either by the division of the underground bulb or through bulbils (also known as bulblets) that form atop the flowering stem. As the bulbils reach maturity, their size and weight pull the tall flowering stem to the ground where the bulbils then take root; slowly “walking” away, season by season, from the parent plant.
I love my Egyptian walking onions so much that I no longer grow bulb onions. Walking onions are extremely hardy, will grow in almost any soil, and are heat- and drought-tolerant and day-length neutral. In fact, when we got our starts we didn’t have time to dig, much less amend the soil, and the only place we had to put them was in red greasy clay. It’s been four years now and I sometimes think of digging them up and doing right by that patch of earth that stays wet all winter and becomes hard as a rock in the dog days of summer — but the walking onions have absolutely thrived there.
The only caveats to growing walking onions are that they have two dormant periods. The first is the deepest, coldest part of winter after a round of bone-chilling temps in the single digits. If you live in a place with long cold winters, expect walking onions to go dormant after a few hard freezes. The second dormancy comes in late summer, some months after the bulbils have completely matured. Yet, as soon as the first cool breeze suggests fall is on the way, an abundance of new leafy growth appears and we’re back to harvesting as much onion “chives” as we can handle and digging up small bulbs throughout the winter.
Many people like to harvest the little bulbils for pickling or to give away to friends to start patches of their own. You can also use your bulbils to grow little storage onions. Gather the largest bulbils in late summer after they are mature and keep them in a cool dark place until early fall. Plant them several inches apart in a well-cultivated bed, mulch and forget about them until the next summer. When the plants send up flowering stalks, cut them off immediately. Allow the plants to go dormant naturally and harvest your well-cured storage onions.
My only advice for those seeking to grow walking onions, particularly Egyptian walking onions, is to try before you buy. Some cultivars are extremely strong in flavor.
Grow a Row
Common bulb onions are typically grown from either sets or plants. Sets are essentially baby onions that have been grown from seed and allowed to develop a small bulb. Once the bulb is big enough, the plant is pulled and the bulbs dried for replanting the following spring. Sets are probably the most popular methods of growing large storage onions. On the other hand, onion plants are grown from seed in late winter and allowed to grow only long enough to establish a good root system before they are dug up, bundled and sold fresh in the spring. If you decide to use onion plants, be sure they’re very fresh. Old, dried out and wilty onion plants don’t produce quality bulbs. Some gardeners find that sets and plants allow them to produce harvest-size onions more quickly than those started from seed at home.
Keep in mind, all varieties of common onions mature in relation to day length. Short-day onions need 10 hours of sunlight each day, while long-day types require up to 15 to trigger bulb formation. If the day length is not long enough for the variety, the bulbs will be small in size. In general, if you live in Zone 7 or below, you should grow only long-day varieties, while those gardening in Zone 8 and above will be best served by planting short-day varieties. Day-neutral onions can be grown in any zone and produce a nice-sized bulb. All onions are typically harvested in late summer after the tops begin to yellow and fall over.
Onions that do not produce large bulbs, such as bunching onions, chives and leeks are always started from seed. Be sure the seed you use is very fresh — those over a season old probably won’t germinate. If the ground is already frozen, start your seeds indoors on a windowsill roughly eight weeks prior to the last spring frost. Sow seed ½ inch deep and 2 inches apart, and allow 10 to 14 days for germination.
Keep the tops trimmed back to about 8 inches tall (this helps the plant put more energy into developing a good root system and keeps the planting manageable). Transplant your onion starts in the garden after danger of a hard freeze has passed and the soil is workable. If you’re worried about cold injury to your young plants, try covering the bed with a single layer of light poly-spun garden fabric.
Of course, you don’t have to start onions from seed indoors to get a good crop, especially if you live in a long-day onion zone. The best way to approach direct-sowing is to prepare a bed in late fall to early winter and direct-sow the seed. If you time it just right, your seeds will germinate, produce a small root and then go dormant with the coming of hard winter weather. In early spring, you can apply a cloak of poly-spun garden fabric to get your onions leafing out as soon as possible. Remove the fabric after danger of a hard freeze has passed. This method is known as “winter sowing,” and it works great on all cold weather spring crops.
To keep a perennial patch of non-bulbing onions going in your garden with very little work, simply allow a few plants of the same variety and species to mature and set seed. Keep in mind that onions that share the same species will cross-pollinate one another. So if you want to keep your onions true, be sure to allow only one variety of each species to set flowers and seed at a time, otherwise you might end up with an undesirable cross. Once the seed ripens you can either gather and scatter it by hand or allow the seeds to fall where they may. You’ll have some thinning to do come spring, but the bounty is virtually endless. Green onions, scallions and chives do especially well when treated this way.
An Ounce of Prevention
Simply eating onions on a regular basis can have a positive effect on your overall health, and because onions and garlic share many of the same chemical constituents, they are often used in similar ways.
One of the best-known uses of onion is in the prevention and treatment of cardiovascular disease. Used alone or with other herbs, onions can aid or ameliorate heart attacks, high blood pressure, arteriosclerosis, blood clots, high cholesterol and angina through their ability to increase blood circulation and viscosity by reducing the amount of fat absorbed into the bloodstream.
Onions also reduce inflammation and fight many types of infections, including fungal infections such as athlete’s foot. Onions are often used to ease the symptoms of colds and flu such as fever, cough and bronchial congestion. They also have strong antibiotic and antimicrobial properties, which are used to inhibit or treat respiratory infections, staphylococcus, streptococcus, cholera, bacillus typhus and dysentery.
Raw or lightly cooked leaves and bulbs should be consumed whenever possible to promote overall health. A flavorful and healing infusion of onion is easily prepared using vegetable, fish or poultry broth. Use as much onion as is palatable.
As a precaution, those persons taking blood-thinning medications or preparing for surgery should talk to their practitioners before using medicinal quantities of onion for circulatory disorders. Other than that, go ahead and indulge, literally, to your heart’s content.
Grow a Little for the Garden
Alliums are not only good for you, but they’re good for your garden, too. When planted in and among vegetables and flowers, Alliums can repel insect and animal pests while attracting beneficials like predatory insects, pollinating bees and beautiful butterflies. The same phytochemicals that make Alliums healthy and flavorful are also fierce fungicidal agents that can be used against powdery mildew and other leaf diseases. A simple tea made with the leaves can be sprayed on many garden plants, including peas and roses, with no worries of harming them, and it might even help repel bad bugs and a curious deer or two. Besides all of the other beneficial characteristics of Alliums, the abundance of bright white, pink and purple flowers does absolute wonders for the gardener’s soul.
I think we can all agree that onions are pretty amazing. With so many incredible, edible onions to choose from, there’s absolutely no excuse not to have at least two or three growing in your garden year-round. Get to know your onions, your health and your garden — your family will thank you for it.
Jill Henderson is an artist, author and organic gardener. She is editor of Show Me Oz, a weekly blog featuring articles on gardening, seed saving, nature ecology, wild edible and medicinal plants and culinary herbs. She has written three books: The Healing Power of Kitchen Herbs, A Journey of Seasons: A Year in the Ozarks High Country and The Garden Seed Saving Guide. This article appeared in the February 2016 issue of Acres U.S.A. magazine.