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[There are separate pages here on scallions, shallots, and leeks.]
Onions growing.

Bulb Onions

(These are what most people think of as just "onions", and they are frequently surprised to find that there are other sorts, some once very popular.)

"All good cooks of this one opinion: no dish savory without an onion." We forget now the exact provenance of that centuries-old saying, but we agree heartily (or at least one of us, the one who was not as a small child fed onion juice and whiskey as a cough syrup, does).

Little by little seed catalogues are starting to acknowledge the crucial but for long unpublicized fact that you cannot grow any onion anywhere. The broad division is into "short day" and "long day" types, because onions are day-length-sensitive (or, in truth, night-length-sensitive). The plants sense the length of the day (or, again, actually of the night) and use that datum to "decide" when to do what in their plantly lives.

The two types differ not only in daylength sensitivity, but in culinary and keeping qualities. The long-day onion class (also called "American") is substantially stronger-tasting, and also is of very much better keeping quality than the short-day (or "European") sort. The common apprehension that short-day types--such as the famed Vidalia--are "sweeter" is quite wrong: they are milder--less pungent--which is not at all the same thing; in fact, the long-day types have more actual sugar, and in consequence actually cook up sweeter (cooking minimizes or reduces the sulfur compounds that give onions their pungency).

In any event, we really have no choice: at our latitude, we must grow long-day (or at least intermediate-day) onions. (If we wanted a "sweet" onion, there is, of course, that famous Walla Walla, an odd exception to the long-day class; but, to us, such onions are "wimp's onions"--if you don't like honest onion flavor, don't use onions, use shallots, or use nothing.)

(The rule of thumb in the U.S. for deciding whether your locale is suited for long-day or short-day types is to imagine a line drawn across the nation from San Francisco to Washington, D.C.: north of that it's long-day, south of it is short-day, all with the usual caveats for a "rule of thumb".)

Connoisseurs (we will strive mightily to avoid the buzzword gourmet) apparently attach real significance to particular varieties of onion (Nero Wolfe, passing through his kitchen, takes a nibble of a raw onion his cook is slicing and asks "Ebenezer?" implying that a discriminating palate can tell one variety from another from but a taste, rather like a wine). But meaningful, realistic flavor comparisons between particular cultivars of onion is essentially nonexistent (there is plenty and plenty of published evaluation, but none we have seen rises to the level of "meaningful, realistic"). But we can at least deal in generalities about the types.

There are three broad classes of onion, identified by color: white; yellow (which includes a sub-class called "brown"); and red. It is consensus agreement that the yellow/brown class is the most pungent when raw but cooks up the sweetest, and is thus best for cooking purposes. The red class is fairly mild and is, for those who are timid about onion flavor, the best for use raw, as on sandwiches or in salads. The white class seems to be a mediocre version of the yellow class, and is valued, if at all, for its color, for the sort of cook who uses white pepper instead of black 9though they taste identical) because the black specks are offensive. (Whites are also reportedly more difficult to grow than yellow/browns, being more susceptible to various diseases.)

Another profoundly important datum is keeping time: the yellow/browns keep very much longer than do the reds (the browns keep longest of all). That is important when one is growing one's own instead of picking up a new supply at the supermarket every week. The best-keeping browns can, some say, under ideal conditions close to to a full year, or at least till close to the time when "baby" onions can be taken from the next crop; the longest-keeping reds are doing well to make 3 or 4 months, and most last far less a time. "Ideal conditions" for onion storage--temperature just over freezing, humidity circa 70%--are not always readily achieved. Most folks hang their storage onions in string bags somewhere indoors (where "indoors" may well be a garage); the ideal, which few can manage, is a drying shed or a root cellar, which depending on local weather conditions. (There are occasional reports of some brown onions lasting even over a full year--one reported an amazing two years.)

There is also a charming onion sub-class called "buttons" or, more commonly, by their Italian name, cippolini. These are not "pearl" or "cocktail" onions; they are smaller, and quite delightful. They are said by some to be hard to grow, but if you have space are worth trying for fun.

Thus, the home grower wants to grow mostly the best-keeping brown available, perhaps supplemented by a small amount of the best-keeping red available for use raw during its window of freshness. (But those who aren't afraid of onion taste probably need not grow reds at all.)

Massive review of the literature available on the web and on usenet suggests that the best yellow/brown "keepers" are these three:

(Aside: why do Australians and new Zealanders do so well at this and North Americans by and large so poorly? Inquiring minds want to know . . . .)

It seems the Pukekohe Longkeeper (also called Pukekohe Long Keeper) has recently been renamed Creamgold; we'll have to see if that change to a more manageable moniker for northeners will help establish its popularity in this hemisphere. Also note that, as with many good but obscure veggie types, seed for all these is offered by members of SSE; you have to be an SSE member to buy, but there are many good reasons you should belong to SSE anyway.

We'd say that the thing to do is plant equal amounts of Australian Brown and Clear Dawn (if you can get both) and see, a year later, which produced and then kept the best overall. (We ourselves won't be doing that this year, as we are just coming back on line to serious gardening and can only take on so many veggies at once.) But certainly the Australian Brown should certainly thrive up here: numerous Canadian seed catalogues, most from Alberta or Sasketchewan, praised it thoughout the 20th century. And the Clear Dawn is being grown in interior British Columbia.

Some red onions of the long-day type also store decently, tough not as well as yellow/browns. Facts beyond vague statements of "good keeper" are hard to come by, but we've done the grunt work, including finding comparative keeping studies. None of those had all the varieties one frequently sees mentioned, but if A is better than B and B is better than C, we can reckon A is better than C. From all that, the three cultivars that emerged as almost surely the best-keeping open-pollinated red onions are:

So if you want to mix in some red onions, we'd go with Red Wethersfield and, if space is plentiful, trial-mix in some Rossa di Milano.

Despite the fact that the Italian onion type called "cipolinni" (literally, "little onions") is often compared to what in the U.S. are known as "pearl onions", the differences are significant. "Pearl " onions are any white (or even yellow) onion harvested when still pretty small; cipolini are a particular kind of onion (a long-day, long-keeping type) with a distinctive set of qualities. They will not be a large fraction of anyone's onion crop, but they are a pleasing specialty and should be included. The Borrettana cipolini seems to be the preferred type. (Note that "long-keeping" is here relative: they're probably good for some months, but equally probably won't compare with a good brown keeper.)

Incidentally: it seems to be consensus that seed-grown onion both grows better and tastes better than onion from "sets."

We're also going to try at some point to establish a bed of so-called "top-setting" or "walking" onions; these curiosities neither bulb nor seed--they form clusters of very small "bulblets" (or "sets") on the tips of their leaf stalks. They are perennials, and can be harvested for use as scallions, plus the bulblets can be used as mini-onions; the bulbs' culinary quality is said to be decent but not outstanding--the trusty Vilmorin guide (1885) says of them "tolerably agreeable to the taste, but rather deficient in delicacy of flavour"--but they are also said to make great pickled onions. If all else we plan for onions works, we probably don't need these, but they make a nice novelty and are reportedly both very hardy and prolifically productive. There are several varieties commonly available; though we located a half dozen such, the two most commonly available are the original Egyptian and an improved strain--which we will use--named the Catawissa, a old red/brown type that is a little hardier and more productive than the original Egyptian.

There are yet other kinds of garden onion--the "potato onion", which is sort of like garlic or shallots in its growth pattern, and the related "multiplier onion"--but we are not going to get involved with those, at least not for a long time.

Potato Onions

Besides the standard bulbing onion described above (and such onion variants as shallots and scallion types), there is a kind once well-known and popular but now faded to an obscure memory: the "potato" (or "multipler") onion. They are a specialized sub-species of the ordinary A. cepa bulb onion, being Allium cepa var. aggregatum. And these little guys should remain of real interest to the home gardener; as the Wikipedia article on them says, "It is remarkably easy to grow, keeps better than almost any other variety of onion, and is ideal for the home gardener with restricted space. It was very popular in the past, but--like many old varieties--it has been passed over in favor of types more suitable for mechanical harvesting and mass marketing."

The potato onion is reputedly a superb "keeping" onion (and the only good-keeping onion that can be grown in short-day latitudes, which is about the southern 2/3 of the U.S.). It is just a little smaller than the standard bulb onion (running from 2 to 4 inches in diameter), but still eminently useful. Their flavor, especially, is described as rich and good but not as strong as that of the standard bulb onion--indeed, they are very close cousins to the shallot, also grown chiefly for its delicacy of flavor (but shallots are much smaller, like large garlic cloves). There is a nice short summary about them from the University of Wisconsin available on line; but it propagates a very common and serious mistake about potato onions that we need to address right now.

The offending line is "Select and save the biggest and best bulbs for replanting in the fall." Since this type can sometimes be quite small, one would think that good advice, but it's not. The curious rule with these is apparently: Planting a small bulb gives a single big-bulbed plant; planting a big bulb gives a cluster of small bulbs. Many first-time growers, unaware of that, do just what that brochure says, then are vastly disappointed by the small bulblets they grow out. Keep enough going that every year you have a mix: small bulblets planted to give you your eating onions, and some big bulbs planted to give you your next season's small seed bulblets.

Once upon a time, one could find all three onion colors--red, yellow, and white--of potato onions in seedsmen's catelogues; no more. Now they are hard to find at all (so far as we can see, only three houses carry them, as yellow varieties). One of those houses is Southern Exposure Seed Exchange, and what they say about the type is well worth reading:

Heirloom potato onions enjoyed widespread popularity before the turn of the century. Nearly every gardener grew potato onions and they were available in yellow, white, and reddish-brown varieties, the yellow being most common. Potato onions are still a local favorite in some areas of Virginia. Each bulb cluster of potato onions may contain many bulbs, averaging 2 to 2-1/2″ in diameter. When a small bulb (3/4″) is planted, it will usually produce one or two larger bulbs. When a large bulb (3 to 4″) is planted, it will produce approximately 10 to 12 bulbs per cluster. These bulbs of various sizes may be used for eating, storing, or replanting. By replanting a mixture of sizes you will have plenty of sets for next year’s crop and plenty of onions for eating during the year. Potato onions can increase 3- to 8- fold by weight each year depending on growing conditions. Potato onions store better than most seed onions, and individual bulbs can be grown in flower pots to produce a steady supply of green onions during the winter.

The discussions below are entirely about standard bulbing onions. For cultural information on potato onions beyond what appears above, just follow the directions pertaining to shallots, except to perhaps increase the planting spacing to 6" or so.


Best results, in quantity and quality, are from onions grown from seed, not from "sets". But beware: onion seeds are notoriously short-lived. If you aren't saving you own seed annually, don't try to be cheap and use last season's leftovers--get fresh seed every year.


Though onions can be direct-seeded hereabouts, it is far wiser to start seedlings indoors, then transplant out--healthy onion seedlings can withstand cold temperatures, even down to 20° F.

Onions grow by first developing their "tops" (above-ground greens), then--when triggered by daylength--setting their bulbs. When they begin to set the bulbs, the tops stop growing. There are two utterly vital points involved here. Rule: an onion plant's bulb will never be bigger than its top. Corollary: grow tops as big as you can get them before bulb formation is triggered.

Around here, bulb formation on long-day cultivars begins sometime between late July and early August. We thus want to get our healthy seedlings into the ground as quickly as practicable, "about 4 to 6 weeks before the last expected spring frost". Since our "last expected spring frost" is around the start of June (review the freeze-date tables), that works back to somewhere from April 15th to May 1st; since our average nightly low on April 15th is 34° and the lowest low on that date was 22°, that target date appears just about right.

Onions want a lot of time in the pot before transplanting, with various sources suggesting anywhere from 7 to 12 weeks. If we take 10 weeks as a reasonable figure, then if we're going to plant out on April 15th, we need to start our seedlings around February 1st.

Starting Seedlings

Onion seed germinates best in the temperature range of about 75° to 85°; as always with germinating, heating pads help hold the wanted temperatures. Keep the growing mix well moistened. Seedlings usually start to emerge at 3 to 5 days; after emergence, the ideal temperature conditions are 60° to 65° daytime and 45° to 60° at night--but just do the best you can.

If, as is likely, you are starting your seedlings under artificial lighting, remember that you are growing long-day onions: keep the light on not over 12 hours each day to give the plants a suitable night period! Otherwise, they will want to bulb up as seedlings.

Many gardeners like to clip growing onion seedlings, sometimes more than once, whenever they reach a height of 4 inches or so, so that they don't flop over or get too "leggy".

The Bed

Onions prefer a sunny, sheltered position in loose, well-drained soil of high fertility with plenty of organic matter worked in. Onions are sensitive to highly acid soils, and grow best when the pH is between 6.5 and 6.8.

Transplanting Out

Prior to transplanting, be sure to give your seedlings a good, long hardening-off--say two weeks--during which you gradually taper off their water (though not drastically) and expose them to outdoor temperatures.

When setting out your transplants, be sure to only just cover their roots with soil, because the bulbs grow on top of the soil. (One source said: "Instead of planting them sticking straight up, we lay them down in a trench and move the soil back over their roots. In about 10 days they're standing up and growing along strongly.")

Space onions at about 4 inches; having a deep-dug or raised bed is good for them, as for all vegetables. Onions crowded too tightly will not develop well.


"Hot" (harsh, overstrong) onions are usually a result of insufficient watering. Onions have a shallow, meagre root system, and need their soil kept continually moist (but not flooded!). They want light but frequent watering--a drip hose might work well.

But . . . as the bulbs approach maturity, the bulbs stop growing and start putting on skin; that is the time to stop watering altogether and let the bulbs finish in dry soil. (And pray it doesn't rain.)

Onion beds need to be kept very well weeded, because weeds easily out-compete onions for water and nutrients, owing to onions' weak root system. But, also because of that shallow, weak system, be sure to cultivate shallowly, with a careful hand and eye, lest you harm the onions themselves.

Since weeding will get you up close and personal with your onions, use the opportunity to keep a close eye out for any flower stalks that might appear--they shouldn't, but they might. If you see any--search out and check some photos for positive identification--just pinch them off at the base (else your onion will bolt and be useless).

While onions like rich soil, avoid using any high-nitrogen based liquid fertilizers when your onions are well along, lest their growing efforts go into their leaves instead of their bulb.

Pull onions when the tops have gone brown and fallen over. Some gardeners break the tops and push them over to try hastening development, but that should not be necessary and may be a bad idea; just grow them and let them do their thing. Don't puncture them in extracting them from the soil. Afetr pulling them, let them dry in the sun for a day or so, then cure and store them as you would garlic or shallots.


Relevant Links

Besides any links presented above on this page, the following ought to be especially helpful.

Odds and Ends


Onions are of the Alliaceae family, the alliums (till recently called the Lilliaecae family). Besides such obvious relatives as leeks, scallions, and garlic, the onion's kin include lillies and hyacinths.


We won't try to re-invent the wheel; here is an excellent on-line history of onions.


If you're here, you probably like onions; but if you don't, you can look in on the Official Homepage of the Anti-Onion League (AOL).

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