Sunday, December 4, 2011

Onion cultivation



Scientific classification

Kingdom         : Plantae
clade               : Angiosperms
clade               : Monocots
Order              : Asparagales
Family             : Amaryllidaceae
Subfamily        : Allioideae
Genus             : Allium
Species           : A. cepa
Binomial name : Allium cepa

The onion (Allium cepa), also known as the bulb onion, common onion and garden onion, is the most widely cultivated species of the genus Allium. The genus Allium also contains a number of other species variously referred to as onions and cultivated for food, such as the Japanese bunching onion (A. fistulosum), Egyptian onion (A. ×proliferum), and Canada onion (A. canadense). The name "wild onion" is applied to a number of Allium species.

The vast majority of cultivars of A. cepa belong to the 'common onion group' (A. cepa var. cepa) and are

usually referred to simply as 'onions'. The 'Aggregatum group' of cultivars (A. cepa var. aggregatum) includes both shallots and potato onions.

Allium cepa is known only in cultivation, but related wild species occur in Central Asia. The most closely related species include Allium vavilovii (Popov & Vved.) and Allium asarense (R.M. Fritsch & Matin) from Iran. However, Zohary and Hopf warn that "there are doubts whether the A. vavilovii collections tested represent genuine wild material or only feral derivatives of the crop."

ONION CULTIVATION

Variety Selection

The size of the onion bulb is dependent upon the number and size of the green leaves or tops at the time of bulb maturity. For each leaf there will be a ring of onion; the larger the leaf, the larger the ring will be. The onion will first form a top and then, depending on the onion variety and length of daylight, start to form the
tree onion

bulb. Onions are characterized by day length; "long-day" onion varieties will quit forming tops and begin to form bulbs when the daylength reaches 14 to 16 hours while "short-day" onions will start making bulbs much earlier in the year when there are only 10 to 12 hours of daylight. A general rule of them is that "long-day" onions do better in northern states (north of 36th parallel) while "short-day" onions do better in states south of that line.

Onions From Seed


Mid to late October is the best time to plant seed of the super sweet, short-to-intermediate daylength onion . Seeds can be sown directly into the garden, covered with one-fourth inch of soil and should sprout within 7- 10 days. If planted thickly, plants can be pulled and utilized as green onions or scallions for salads or fresh eating in 8-10 weeks. However, most gardeners want to grow an onion bulb as large as a basketball. To do this, the onion plants must be thinned by next February until they are at least 2-3 inches apart to insure adequate bulb expansion. The removed plants can be used for scallions or for transplanting into another area of the garden so that these too will have adequate space in which to enlarge into large bulbs.

Fertilization of onion plants is vital to success. Research findings indicate that onion growth and yield can be greatly enhanced by banding phosphorus 2-3 inches below seed at planting time. This phosphorus acts as a starter solution which invigorates the growth of young seedlings. Banding phosphorus, such as super phosphate (0-20-0), 2-3 inches below the seed involves making a trench 3 inches deep, distributing one-half cup of super phosphate per 10 row feet, covering the phosphate with soil, sowing seed and covering lightly with one-half inch or less of soil. Once established, onion plants should receive additional amounts of fertilizer (21-0-0 - Ammonium sulfate or Ammonium nitrate) as a side-dress application every month.



Flowering causes a decrease in bulb size as well as a central flower stalk which enhances decay during storage. This is exactly what will happen to those who are planting onion transplants or sets in October or November with the hope of large onions next spring. The onion bulbs which produce a flower stalk may be large but they will be light-weight (one-half the weight of a comparable size, non-flowered onion bulb) and prone to decay. The best way to insure success is to either plant the onion seed from October 1 until November 15 or plant transplants from January through February  .


Transplantation

After  receiving live plants, they should be planted as soon as possible. If  plants are not  planted right away,
the onion plants are to be removed from the box and spread them out in a cool, dry area. The roots and tops may begin to dry out but need  not be alarmed, the onion is a member of the lily family and as such will live for approximately three weeks off the bulb. The first thing that the onion will do after planting will be to shoot new roots.

Preparing the Soil

Onions are best grown on raised beds at least four inches high and 20 inches wide. Onion growth and yield can be greatly enhanced by banding a fertilizer rich in phosphorous (10-20-10) 2 to 3 inches below
onion seeds

transplants at planting time. A trench is to be made on the top of the bed fours inches deep, distribute one-half cup of the fertilizer per 10 linear feet of row, cover the fertilizer with two inches of soil and plant the transplants.


Planting

Plants to be set out approximately one inch deep with a four inch spacing. On the raised bed, two rows on each bed to be set , four inches in from the side of the row. If some green onions are  to be  harvested during the growing season as green onions, then plants  may be  planted as close as two inches apart. Every other one is to be pulled out, prior to them beginning to bulb, leaving some for larger onions.


Fertilization and Growing Tips

Onions require a high source of nitrogen. A nitrogen-based fertilizer (ammonium sulfate or ammonium nitrate) should be applied at the rate of one cup per twenty feet of row. The first application should be about three weeks after planting and then continue with applications every 2 to 3 weeks. Once the neck starts feeling soft do not apply any more fertilizer. This should occur approximately 4 weeks prior to harvest. Always water immediately after feeding and maintain moisture during the growing season. The closer to harvest the more water the onion will require. For weed control a pre-emergent herbicide (DACTHAL in USA) should be applied prior to planting. This will provide weed control for approximately one month after planting. Other products such as GOAL and BUCTRIL, can assist in weed control during the growing season.  For organic gardeners a rich compost high in Nitrogen should be incorporated into the soil.  As the onion begins to bulb the soil around the bulb should be loose so the onion is free to expand.


Disease and Insect Control

The two major diseases that will affect onions are blight and purple blotch. Should the leaves turn pale-green, then yellow, blight has probably affected the plant. Purple blotch causes purple lesions on the leaves. Heavy dew and foggy weather favor their rapid spread, and when prolonged rainy spells occur in warm weather, these diseases can be very destructive. The best cure is prevention: use only well-drained soil, run the rows in the same direction as prevailing wind and avoid windbreaks or other protection. Should conditions persist, a spray with a multipurpose fungicide such as daconil(in USA) can be applied on a 7 to 10 day schedule.

The insect that causes the most damage is the onion thrip. They feed by rasping the surface of the leaves and sucking the liberated juices. They are light-brown in color and are approximately 1mm long. The most available insecticides are Malathion or Diazinon, or an insecticidal soap or biological insecticide may be used.

Flowering 

Flowering of onions can be caused by several things but usually the most prevalent is temperature fluctuation. An onion is classed as a biennial which means it normally takes 2 years to go from seed to seed. Temperature is the controlling or triggering factor in this process. If an onion plant is exposed to alternating cold and warm temperatures resulting in the onion plant going dormant, resuming growth, going dormant and then resuming growth again, the onion bulbs prematurely flower or bolt. The onion is deceived into believing it has

completed two growth cycles or years of growth in its biennial life cycle so it finalizes the cycle by blooming. Flowering can be controlled by planting the right variety at the right time. Use only transplants that are pencil-sized or smaller in diameter when planting in early spring or always plant seed .

What To Do About Flowering?

What can one do if flower stalks appear? Should the flower stalks be removed from the onion plants? Suit yourself but once the onion plant has bolted, or sent up a flower stalk, there is nothing you can do to eliminate this problem. The onion bulbs will be edible but smaller. Use these onions as soon as possible because the green flower stalk which emerges through the center of the bulb will make storage almost impossible. Seedstalk formation (bolting) of garlic is not induced by exposure to fluctuating temperatures, as is the case with onions, which means that a wide range of fall planting dates is permissible for this crop. Seedstalk

formation is also not damaging to garlic since the cloves are arranged around the seedstalk and will be removed from the dried seedstalk. Conversely, the edible onion bulb is penetrated by the seedstalk which is hard when the bulb is harvested, but prematurely decays causing loss of the entire bulb in storage. When the tops become yellowish and partly dry, garlic is ready for harvest.

Harvesting And Storage

Onions are fully mature when their tops have fallen over. After pulling from the ground allow the onion to dry, clip the roots and cut the tops back to one inch. The key to preserving onions and to prevent bruising is to

keep them cool, dry and separated. In the refrigerator, wrapped separately in foil, onions can be preserved for as long as a year. The best way to store onions is in a mesh bag or nylon stocking. Place an onion in the bag and tie a knot or put a plastic tie between the onions and continue until the stocking is full. Loop the stocking over a rafter or nail in a cool dry building and when an onion is desired, simply clip off the bottom

onion with a pair of scissors or remove the plastic tie. Another suggestion is to spread the onions out on a screen which will allow adequate ventilation, but remember to keep them from touching each other. As a general rule, the sweeter the onion, the higher the water content, and therefore the less shelf life. A more pungent onion will store longer so eat the sweet varieties first and save the more pungent onions for storage.

Uses

Onions are often chopped and used an ingredient in various hearty warm dishes, although onions can also be a more prominent ingredient, for example in French onion soup, or be used raw in cold salads. Onions pickled in vinegar are eaten as a snack. These are often served as a side serving in fish and chip shops throughout the United Kingdom and Australia, often served with cheese in the United Kingdom, and are referred to simply as "pickled onions" in Eastern Europe.

Onion types and products

Common onions are normally available in three colors: yellow, red, and white. Yellow onions are full-flavored and are a reliable standby for cooking almost anything. Yellow onions turn a rich, dark brown when cooked and give French onion soup its tangy sweet flavor. The red onion is a good choice for fresh uses or in grilling and char-broiling. White onions are the traditional onion used in classic Mexican cuisine. They have a golden color and sweet flavor when sautéed.

While the large mature onion bulb is the onion most often eaten, onions can be eaten at immature stages. Young plants may be harvested before bulbing occurs and used whole as scallions. When an onion is harvested after bulbing has begun but the onion is not yet mature, the plants are sometimes referred to as summer onions.

Additionally, onions may be bred and grown to mature at smaller sizes. Depending on the mature size and the purpose for which the onion is used, these may be referred to as pearl, boiler, or pickler onions.

(However, true pearl onions are a different species.) Pearl and boiler onions may be cooked as a vegetable rather than an ingredient. Pickler onions are, unsurprisingly, often pickled.

Onion seed may be "sprouted", and the resulting sprouts used in salads, sandwiches, and other dishes.

Onions are available in fresh, frozen, canned, caramelized, pickled, powdered, chopped, and dehydrated forms.

Onion powder is a spice used for seasoning in cooking. It is made from finely ground, dehydrated onions, mainly the pungent varieties of bulb onions, which causes the powder to have a very strong odor. Onion powder comes in a few varieties: white, yellow, red and toasted.

Culinary uses

Onions have particularly large cells that are readily observed at low magnification; consequently, onion tissue is frequently used in science education for demonstrating microscope usage.

Onion skins have been used for dye.

Historical uses

Bulbs from the onion family are thought to have been used as a food source for millennia. In Bronze Age settlements, traces of onion remains were found alongside fig and date stones dating back to 5000 BC.

However, it is not clear if these were cultivated onions. Archaeological and literary evidence such as the Book of Numbers 11:5 suggests cultivation probably took place around two thousand years later in ancient Egypt,

at the same time that leeks and garlic were cultivated. Workers who built the Egyptian pyramids may have been fed radishes and onions.

The onion is easily propagated, transported and stored. The ancient Egyptians worshipped it, believing its spherical shape and concentric rings symbolized eternal life. Onions were even used in Egyptian burials, as evidenced by onion traces being found in the eye sockets of Ramesses IV.

In ancient Greece, athletes ate large quantities of onion because it was believed to lighten the balance of blood. Roman gladiators were rubbed down with onion to firm up their muscles. In the Middle Ages, onions were such an important food that people would pay their rent with onions, and even give them as gifts. Doctors were known to prescribe onions to facilitate bowel movements and erections, and also to relieve headaches, coughs, snakebite and hair loss.

The cultivated onion was introduced to North America by Christopher Columbus on his 1492 expedition to Hispaniola; however, they found that strains of wild onions already grew throughout North America. Native American Indians used wild onions in a variety of ways, eating them raw or cooked, as a seasoning or as a vegetable. Such onions were also used in syrups, as poultices, as an ingredient in dyes and even as toys.

Onions were also prescribed by doctors in the early 16th century to help with infertility in women, and even dogs, cats and cattle and many other household pets. However, recent evidence has shown that dogs, cats, guinea pigs, and other animals should not be given onions in any form, due to toxicity during digestion.

Medicinal properties and health effects of onions

Wide-ranging claims have been made for the effectiveness of onions against conditions ranging from the common cold to heart disease, diabetes, osteoporosis, and other diseases. They contain chemical compounds believed to have anti-inflammatory, anticholesterol, anticancer, and antioxidant properties, such as quercetin. Preliminary studies have shown increased consumption of onions reduces the risk of head and neck cancers.

Among all varieties, Asian white onions have the most eye irritating chemical reaction. Regular use of white onion, if eaten raw, is claimed to be good due to its antioxidant and anti-inflammatory properties.

In India some sects do not eat onions as they believe them to be an aphrodisiac; various schools of Buddhism also advise against eating onions and other vegetables of the Allium family.

An application of raw onion is also said to be helpful in reducing swelling from bee stings.

Onions may be beneficial for women, who are at increased risk for osteoporosis as they go through menopause, by destroying osteoclasts so they do not break down bone.

An American chemist has stated the pleiomeric chemicals in onions have the potential to alleviate or prevent sore throat. Onion in combination with jaggery has been widely used as a traditional household remedy for sore throat in India.

Shallots have the most phenols, six times the amount found in Vidalia onion, the variety with the lowest phenolic content. Shallots also have the most antioxidant activity, followed by Western Yellow, pungent yellow , Northern Red, Mexico, Empire Sweet, Western White, Peruvian Sweet, Texas 1015, Imperial Valley Sweet, and Vidalia. Western Yellow onions have the most flavonoids, eleven times the amount found in Western White, the variety with the lowest flavonoid content.

For all varieties of onions, the more phenols and flavonoids they contain, the more reputed antioxidant and anticancer activity they provide. When tested against liver and colon cancer cells in laboratory studies, 'Western Yellow', pungent yellow (New York Bold)[28] and shallots were most effective in inhibiting their growth. The milder-tasting cultivars (i.e., 'Western White,' 'Peruvian Sweet,' 'Empire Sweet,' 'Mexico,' 'Texas 1015,' 'Imperial Valley Sweet' and 'Vidalia') showed little cancer-fighting ability.

Shallots and ten other onion (Allium cepa L.) varieties commonly available in the United States were evaluated: Western Yellow, Northern Red, pungent yellow , Western White, Peruvian Sweet, Empire Sweet, Mexico, Texas 1015, Imperial Valley Sweet, and Vidalia. In general, the most pungent onions delivered many times the effects of their milder cousins.

The 3-mercapto-2-methylpentan-1-ol in onion was found to inhibit peroxynitrite-induced mechanisms in vitro.

While members of the onion family appear to have medicinal properties for humans, they can be deadly for dogs, cats, and guinea pigs.

Eye irritation

Onions are sliced or eaten, cells are broken, allowing enzymes called alliinases to break down amino acid sulphoxides and generate sulphenic acids. A specific sulfenic acid, 1-propenesulfenic acid, formed when onions are cut, is rapidly rearranged by a second enzyme, called the lachrymatory factor synthase or LFS, giving syn-propanethial-S-oxide, a volatile gas known as the onion lachrymatory factor or LF. The LF gas diffuses through the air and eventually reaches the eye, where it activates sensory neurons, creating a stinging sensation. Tear glands produce tears to dilute and flush out the irritant.Chemicals that exhibit such an effect on the eyes are known as lachrymatory agents.

Supplying ample water to the reaction while peeling onions prevents the gas from reaching the eyes. Eye irritation can, therefore, be avoided by cutting onions under running water or submerged in a basin of water. Another way to reduce irritation is by chilling, or by not cutting off the root of the onion (or by doing it last), as the root of the onion has a higher concentration of enzymes. Using a sharp blade to chop onions will limit the cell damage and the release of enzymes that drive the irritation response. Chilling or freezing onions prevents the enzymes from activating, limiting the amount of gas generated.

Eye irritation can also be avoided by having a fan blow the gas away from the eyes, or by wearing goggles or any eye protection that creates a seal around the eye. Contact lens wearers may also experience less immediate irritation as a result of the slight protection afforded by the lenses themselves.

The amount of sulfenic acids and LF released and the irritation effect differs among Allium species. On January 31, 2008, the New Zealand Crop and Food institute created a strain of "no tears" onions by using gene-silencing biotechnology to prevent synthesis by the onions of the lachrymatory factor synthase enzyme.

Propagation

Onions may be grown from seed or, more commonly today, from sets started from seed the previous year. Onion sets are produced by sowing seed very thickly one year, resulting in stunted plants that produce very small bulbs. These bulbs are very easy to set out and grow into mature bulbs the following year, but they have the reputation of producing a less durable bulb than onions grown directly from seed and thinned.

Seed-bearing onions are day-length sensitive; their bulbs begin growing only after the number of daylight hours has surpassed some minimal quantity. Most traditional European onions are what is referred to as "long-day" onions, producing bulbs only after 15+ hours of daylight occur. Southern European and North African varieties are often known as "intermediate day" types, requiring only 12–13 hours of daylight to stimulate bulb formation. Finally, "short-day" onions, which have been developed in more recent times, are planted in mild-winter areas in the fall and form bulbs in the early spring, and require only 9–10 hours of sunlight to stimulate bulb formation.

Either planting method may be used to produce spring onions or green onions, which are the leaves of immature plants. Green onion is a name also used to refer to another species, Allium fistulosum, the Welsh onion, which does not form bulbs.

The tree onion produces bulblets instead of flowers and seeds, which can be planted directly in the ground.

I'itoi onion (Allium cepa) is a prolific multiplier onion cultivated near Baboquiviri, Arizona. They have a shallot-like flavor. They are easy to grow and ideal for hot, dry climates. To grow them, separate bulbs, and plant in the fall 1 inch below surface and 12 inches apart. Bulbs will multiply into clumps and can be harvested throughout the cooler months. Tops will die back in the heat of summer and may return with monsoon rains; bulbs can remain in the ground or be harvested and stored in a cool dry place for planting in the fall. The plants rarely flower; propagation is by division.

Raw OnionsNutritional value per 100 g (3.5 oz)

Energy                              166 kJ (40 kcal)
Carbohydrates                  9.34 g
- Sugars                            4.24 g
- Dietary fiber                    1.7 g
Fat                                     0.1 g
- saturated                         0.042 g
- monounsaturated             0.013 g
- polyunsaturated               0.017 g
Protein                              1.1 g
Water                             89.11 g
Vitamin A equiv                  . 0 μg (0%)
Thiamine (vit. B1)             0.046 mg (4%)
Riboflavin (vit. B2)           0.027 mg (2%)
Niacin (vit. B3)                0.116 mg (1%)
Vitamin B6                       0.12 mg (9%)
Folate (vit. B9)               19 μg (5%)
Vitamin B                    12 0 μg (0%)
Vitamin C                      7.4 mg (9%)
Vitamin E                       0.02 mg (0%)
Vitamin K                       0.4 μg (0%)
Calcium                           23 mg (2%)
Iron                              0.21 mg (2%)
Magnesium                   0.129 mg (0%)
Phosphorus                 29 mg (4%)
Potassium                  146 mg (3%)
Sodium                          4 mg (0%)
Zinc                          0.17 mg (2%)

Varieties

Common onion group (var. cepa)

Most of the diversity within A. cepa occurs within this group, the most economically important Allium crop. Plants within this group form large single bulbs, and are grown from seed or seed-grown sets. The majority of
white onoin

cultivars grown for dry bulbs, salad onions, and pickling onions belong to this group. The range of diversity found among these cultivars includes variation in photoperiod (length of day that triggers bulbing), storage life, flavour, and skin colour.

European onions

A number of onions have Protected Geographical Status in Europe, these include:

Cipolla Rossa di Tropea, a red onion from Calabria, Italy (PGI)
Cipollotto Nocerino, a spring/salad onion-sized Allium Ccepa from Campania, Italy (PDO)
Oignon doux des Cévennes, a sweet onion from the south east of France (PDO)

Aggregatum group (var. aggregatum)

This group contains shallots and potato onions, also referred to as multiplier onions. The bulbs are smaller than those of common onions, and a single plant forms an aggregate cluster of several bulbs. They are
cluster onions(aggregatum onions)

propagated almost exclusively from daughter bulbs, although reproduction from seed is possible. Shallots are the most important subgroup within this group and comprise the only cultivars cultivated commercially. They

form aggregate clusters of small, narrowly ovoid to pear-shaped bulbs. Potato onions differ from shallots in forming larger bulbs with fewer bulbs per cluster, and having a more flattened (onion-like) shape. However, intermediate forms exist.

Species that may be confused with A. cepa

Scallions or salad onions may be grown from the Welsh onion (A. fistulosum) as well as from A. cepa. Young plants of A. fistulosum and A. cepa look very similar, but may be distinguished by their leaves, which are circular in cross-section in A. fistulosum rather than flattened on one side.

Hybrids with A. cepa parentage

A number of hybrids are cultivated that have A. cepa parentage, such as the tree onion or Egyptian onion (A. ×proliferum), Wakegi onion (A. ×wakegi), and the triploid onion (A. ×cornutum).

Diploid hybrids

The tree onion or Egyptian onion produces bulblets in the flower head instead of flowers, and is now known to be a hybrid of A. cepa × A. fistulosum. It has previously been treated as a variety of A. cepa, for example A. cepa var. proliferum, A. cepa var. bulbiferum, and A. cepa var. viviparum.

The Wakegi onion is also known to be a hybrid between A. cepa and A. fistulosum, with the A. cepa parent believed to be from the 'aggregatum' group of cultivars. It has been grown for centuries in Japan and China for use as a salad onion.

Under the rules of botanical nomenclature, both the Egyptian onion and Wakegi onion should be combined into one hybridogenic species, having the same parent species. Where this is followed, the Egyptian onion is

named A. ×proliferum 'Eurasian group' and the Wakegi onion is named A. ×proliferum 'East Asian group'.

Triploid onions

The triploid onion is a hybrid species with three sets of chromosomes, two sets from A. cepa and the third set from an unknown parent. Various clones of the triploid onion are grown locally in different regions, such as 'Ljutika' in Croatia, and 'Pran', 'Poonch' and 'Srinagar' in the India-Kashmir region. 'Pran' is grown extensively in the Northern Indian provinces of Jammu and Kashmir. There are very small genetic differences between 'Pran' and the Croatian clone 'Ljutika', implying a monophyletic origin for this species.

Some authors have used the name A. cepa var. viviparum (Metzg.) Alef. for the triploid onion, but this name has also been applied to the Egyptian onion. The only name unambiguously connected with the triploid onion is A. ×cornutum.

Japanes Bunching Onions

Botanical name: Allium fistulosum
Japanese bunching onion

Bunching Onions are also called Japanese Bunching Onions, Welsh Onions, or Scallions. Although growing Bunching Onions can be grown as annuals, one  can leave a few plants in the organic garden to allow
Japanese white bunch onion

offshoots to develop for dividing the following year.

Bunching Onions are to carefully harvested by gently pulling older ones up allowing the young onions remain in the soil to grow.

Bunching onions are mild and can be used fresh or like any green onions.

Planting

In garden spacing (inches)                              :  3  
In flat spacing (inches)                                    :  Broadcast  
Planting depth (inches)                                    :  Cover seed with soil.
Maxiumum number of plants per square foot   :  25
Nutrient relationship                                        :  Light Feeder

Harvest

Days to maturity                                  : 56-119
Harvesting period (days)                      : -
Minimum yields in pounds /square foot : 1

Cultural


Diseases: Botrytis Leaf Blight, Damping-Off, Downy Mildew, Fusarium Basal Rot, Neck Rot, Onion Smut, Pink Root, Purple Blotch, Several Bacteria, White Rot.
red beard bunching onion

Insect pests:(Insect Pest Finder) Army Cutworm, Cutworm, Green Peach Aphid, Greenhouse Whitefly, Leafminer, Northern Mole Cricket, Onion Eelworm, Onion Maggot, Onion Thrips, Saltmarsh Caterpillar, Slugs and Snails, Spotted Cucumber Beetle, Striped Cucumber Beetle, Vegetable Weevil

Varieties

Evergreen Hardy White, White Spear, Deep Purple

Storage
Green onion and leeks are optimally stored refrigerated. Cooking onions and sweet onions, on the other hand, can be stored at room temperature, optimally in a single layer, in mesh bag in a dry, cool, dark, well ventilated location. In this environment, cooking onions have a shelf life of 3 to 4 weeks, and sweet onions 1 to 2

weeks. Cooking onions will absorb odours from apples and pears. Also, they draw moisture from vegetables they are stored with which may cause them to decay. Sweet onions have a greater water and sugar content than cooking onions. This makes them sweeter and milder tasting, but also reduces their shelf life. Sweet onions can also be stored refrigerated; they have a shelf life of approximately 1 month, optimally uncovered. Irrespective of type, any cut pieces of onion are optimally tightly wrapped, stored away from other produce, and used within 2 to 3 days.


Onion (Allium cepa), herbaceous biennial plant and its edible bulb. The onion is probably native to southwestern Asia but is now  grown throughout the world, chiefly in the temperate zones. The plant belongs to the lily family, Alliaceae; however, some classifications place it in the family Liliaceae. Most members of both families have an underground storage system, such as a bulb or tuber. Other members of this family include ornamental plants such as the tulip, hyacinth, and lily-of-the-valley and edible plants such as the leek, garlic, and chive.

The common onion has one or more leafless flower stalks that reach a height of 0.75–1.8 m (2.5–6 feet), terminating in a cluster of small greenish white flowers. The leaf bases of the developing plant swell to form the underground bulb that is the mature, edible onion. Most commercially cultivated onions are grown from the plant’s small black seed, which is sown directly in the field, but onions may also be grown from small bulbs or from transplants. Onions are among the hardiest of all garden vegetable plants.

Onions are among the world’s oldest cultivated plants. They were probably known in India, China, and the Middle East before recorded history. Ancient Egyptians regarded the spherical bulb as a symbol of the universe, and its name is probably derived from the Latin unus, meaning “one.” The Romans introduced the onion to Britain and, in the New World, American Indians added a highly pungent wild onion to their stews. Curative powers have been attributed to onions throughout the centuries; they have been recommended for such varied ailments as colds, earaches, laryngitis, animal bites, powder burns, and warts.

Onions are used widely in cooking. They add flavour to such dishes as stews, roasts, soups, and salads, and are also served as a cooked vegetable. The onion’s characteristic pungency results from the sulfur-rich volatile oil it contains. Release of this oil during peeling brings tears to the eyes, but many cooks claim that tears can be avoided by peeling onions under running water.

Onions vary in size, shape, colour, and pungency. Warmer climates produce onions with a milder, sweeter flavour than do other climates.

Globe-shaped onions may be white, yellow, or red. They have strong flavour and are used chiefly for soups, stews, and other prepared dishes and for frying.


Bermuda onions are large and flat, with white or yellow colour and fairly mild taste. They are often cooked and may be stuffed, roasted, or French-fried. They
are also sliced and used raw in salads and sandwiches.

Spanish onions are large, sweet, and juicy, with colour ranging from yellow to red. Their flavour is mild, and they are used raw and sliced for salads and sandwiches and as a garnish.

Italian onions are flat, with red colour and mild flavour. They are used raw for salads and sandwiches, and their red outer rings make an attractive garnish.

Pearl onions are not a specific variety but are small, round, white onions harvested when 25 mm (1 inch) or less in diameter. They are usually pickled and used as a garnish and in cocktails. Small white onions that are picked when between 25 and 38 mm in diameter are used to flavour foods having fairly delicate taste, such as omelets and other egg dishes, sauces, and peas. They are also served boiled or baked.

Green onions, also called scallions and spring onions, are young onions harvested when their tops are green and the underdeveloped bulbs are 13 mm or less in diameter. Their flavour is mild, and the entire onion, including top, stem, and bulb, is used raw in salads and sauces, as a garnish, and also as a seasoning for prepared dishes.

Egyptian Walking Onions

As their scientific name "Allium proliferum" states, these hardy little onions are very "prolific." After planting them in the garden one will have onions every year for years to come. Egyptian Walking Onions are also called "Tree Onions, Egyptian Tree Onions, Top Onions, Winter Onions, or Perennial Onions."


The wonderful walking onion.

Egyptian Walking Onions are one of the first plants to emerge in the spring. The leaves poke up through the soil like little green spikes and shoot towards the sky despite the frost or snow. The blue-green leaves are

round and hollow and will grow up to 3 feet in height. At the the end of a leaf stalk, at the top of the plant, a cluster of bulblets will begin to grow. These bulblets are also known as "bulbils" or "sets."  Every Egyptian Walking Onion plant will produce a cluster of sets at the top, hence the name, "Top Onion," meaning they are top-setting onions.

Egyptian Walking Onions are top-setting onions.



Egyptian Walking Onion topsets first appear in early spring encased in a protective papery tunic which has a

curled tip reminiscent of an elf's shoe. As they grow, this papery capsule will tear open and eventually fall off.


Egyptian Walking Onion paper tunics

The topsets reach maturity in late summer. Many of them have little green sprouts and mini root nodules. They look like mini versions of the parent plant. When the sets become heavy enough, they will pull the plant over

to the ground. If the soil conditions are right, the fallen sets will take root and grow into new Egyptian Walking Onion plants, hence the name, "Walking Onion." They will literally walk across your garden!


Egyptian Walking Onion plants caught in the act of walking!

Although the Egyptian Walking Onion is a top-setting onion, it will occasionally produce miniature flowers among its sets. The flowers are about 1/4" wide. They have 6 white petals and 6 stamens. Each petal has a

vertical pea-green stripe. Most of the flowers dry up and wither as the sets compete with them for energy. So an Egyptian Walking Onion seed is a rarity - at least I've never seen a mature and viable one.


Miniature Egyptian Walking Onion flowers.



An Egyptian Walking Onion set looks like, and essentially is, a miniature onion. Sets produced by these plants are generally smaller than the ordinary annual garden variety onion sets. They range in size from 1/4 inch to 1 inch in diameter. Each cluster can have as few as 2 sets, or as many as 30 sets. Sometimes a new leaf stalk will emerge from a cluster of top-sets like a little branch, and a second cluster will grow from it, hence the name, "Tree Onion."


The Tree Onion: top sets are branching from top sets.

In the ground, the Egyptian Walking Onion plant produces a small shallot-like onion which can be harvested. Once harvested, however, the plant will obviously not grow back. If left in the ground, the onion will produce offsets and form a group of onions. New leaves and topsets will grow from the onions each year. The Egyptian Walking Onion is a perennial onion.

How and when to plant your Egyptian Walking Onion sets

Plant each "set" in the soil about 1-2 inches deep in full sun. Soil should be slightly moist and well drained. Egyptian Walking Onions hate wet feet! Plant in rows about 1 foot apart. The sets should be spaced approximately 3-6 inches apart in each row. Plant in full sunlight. Egyptian Walking Onion sets can also be planted in clusters. When planted this way they make a great addition to your herb garden. They can even be planted in pots to be kept outside or indoors. They can be planted any time of the year even in the winter as long as the ground isn't frozen or covered with snow. However, fall is the optimal time to plant them so they can develop a strong root system and be ready for good growth the following spring. NOTE: Egyptian Walking Onions sets will not produce topsets during their first year of growth. Topsets will grow during the plant's second year and every year thereafter. The following is a list of what to expect when planting your sets at different times of the year:Spring:
Sets will grow throughout the spring and summer and develop tall green leaves and bulb/root growth in the ground. Since it is the plant's first growing season, it will probably not produce topsets.

Summer:

Sets planted at this time will grow roots and leafstalks, and have some onion bulb development in the ground, but they will not produce topsets.

Fall:

Sets planted at this time will grow roots and leafstalks only. The leafstalk will die back for the winter. The onion bulb will develop a little in the ground and store enough energy to carry the plant through the winter. A leafstalk will reemerge in the spring and the plant will grow throughout the spring and summer to maturity.

Winter: Sets are planted at this time of the year only if the soil is not frozen solid. If you can dig a 1" to 2" deep hole in the soil, then you can plant your sets. The sets will not grow much at all - maybe a little bit of root growth only, unless you live where the winters are mild. If this is the case, you might also get a leafstalk. When planting in the winter, mulching is a good idea. In fact, mulching is good practice at any time of the year. Mulching keeps the weeds down, prevents unnecessary water evaporation and erosion, and fertilizes your plants.

Egyptian Walking Onions are perennial plants and will grow back each year and yield new and bigger clusters of sets on the top and new onion offsets in the soil. During their first year of growth they will not produce topsets. You might see only greens. But don't be disappointed, your Egyptian Walking Onion plants will grow back the following year in full force and produce their first clusters of topsets. Once established, plants may be propagated by division or by planting the sets that grow from the top. Egyptian Walking Onions are extremely hardy plants. Our plants have endured harsh winters with temperatures plummeting down to -24° below zero! Hence the name, "Winter Onion." They grow well in zones 3-9.

How to harvest your Egyptian Walking OnionsHarvesting the topsets: 

In mid to late summer and autumn the top-sets may be harvested. The optimal time to pluck off the topsets is when the leafstalk has dried and turned brown. More than likely, it has fallen over by this time. Be sure to remove any topsets that have fallen to the ground if you do not want them to self-sow in their new locations. Despite their name, these plants are very easy to control and keep from spreading just by harvesting the top-sets.

Harvesting the greens: 

The greens (leaves) may be cut and harvested at any time. If you harvest all the greens from one plant, the plant will probably not be able to produce topsets for that year. If the plant is producing several leaf stalks, just harvest one or two of smaller side leaves, and the plant should still produce topsets. Soon after you have harvested the leaves from an Egyptian Walking Onion plant, new leaves will start to grow in their place which can be harvested again. If you live in a mild climate, your Egyptian Walking Onion plant may produce greens all year round. In the fall after the topsets have matured and fallen to the ground, or after they have been harvested, new greens will start to grow - yummy!

Harvesting the onion bulbs in the ground: The onions at the base of the plant that are growing in the ground can be harvested in late summer and fall. Be sure to leave some onions in the ground for next year's crop. An Egyptian Walking Onion bulb is about the same size and shape as a shallot. Bigger bulbs may be obtained by cutting off the topsets before they develop. That way the plant can put its energy into the onion bulb in the ground instead of into the topsets. Note: if you harvest the onion bulb in the ground, you will destroy the plant - it will not grow back next year. So, if you want to eat the onion bulbs in the ground, make sure to replace them by planting topsets, or offsets from the bulb.

How to eat your Egyptian Walking Onions

Egyptian Walking Onions taste just like a regular onion, only with a bit more pizzazz! The entire plant can be eaten. Small onions form at the base in the soil. They can be eaten and prepared just like any other onion. The hollow greens may be chopped to eat like chives or green onions. They are excellent when fried, cooked in soups, or raw in salads (my favorite). The bulblets that grow from the top are excellent when peeled and fried. You can even pickle them. Or just pop them in your mouth like popcorn! Watch out, they're a little spicy!

Egyptian Walking Onion names

Taxonomic names: the following three scientific names refer to the Egyptian Walking Onion plantAllium cepa var. proliferum

Egyptian Walking Onions are proliferous. A proliferous plant produces new individuals by budding. This type of plant also produces offshoots, especially from unusual places. In the case of the Egyptian Walking Onion, an offshoot will grow out form cluster of sets. Proliferous plants produce an organ or shoot from an organ that is itself normally the last, as a shoot or a new flower from the midst of a flower. In the case of the Egyptian Walking Onion, a cluster of topsets grows from a cluster of topsets forming a multi-tiered plant.

Allium cepa var. bulbiferous


Egyptian Walking Onions are bulbiferous. They produce bulbs!
Allium cepa var. viviparum
Egyptian Walking Onions are viviparous. They produce bulbils or new plants rather than seed. Egyptian Walking Onion sets germinate while still attached to the parent plant. They can be seen growing leaves and roots before they ever touch the ground.

Common names:"Egyptian Walking Onion" or "Walking Onion"

The name "Egyptian" is very mysterious. The ancient Egyptians worshipped onions. They believed that its spherical shape and concentric rings symbolized eternal life. Onions were even used in Egyptian burials for the pharaohs. Small onions were found in the eye sockets of Ramesses IV. It is not known whether this particular species of onion came from the Egyptians or not. The "Egyptian" part of the name remains a mystery. Maybe the name refers to the way they walk.....do they "walk like an Egyptian?"

The name "Walking Onion" was given to this plant because it literally walks to new locations. When the cluster of topsets becomes heavy enough, it will pull the plant over to the ground. Depending on how tall the plant is and where the bend occurs, the topsets may fall up to 3 feet away from the base of the plant. Here they will take root and grow new plants. When these new plants mature, their topsets will eventually fall to the ground and start the process all over again. Egyptian Walking Onion plants can walk between 1 and 3 feet per year!

"Tree Onion"

Egyptian Walking Onions are known for their ability to grow a twisting stalk from the cluster of sets at the top of the plant. Another cluster of sets will grow at the end of this second stalk giving the plant a branching, tree-like appearance.

"Top Onion", "Topset Onion", or "Top Setting Onion"
Egyptian Walking Onions grow a cluster of sets at the top of the plant instead of seeds.
"Winter Onion"
These Onions can survive freezing cold winters with temperatures plummeting well below -24°F! They are hardy to zone 3.

Egyptian Walking Onion taxonomy

Kingdom                          : Plantae (plants)
Division                            : Magnoliophyta (flowering plants)
Class                                : Liliopsida (monocotyledon - having one seed leaf)
Order                               : Liliales (lily family, water-hyacinth family, iris family)
Family                              : Alliaceae (lily family)
Genus                               : Allium (onion)
Species                             : cepa
Variations                          : proliferum
                                           bulbiferum
                                           viviparum all are synonymous

Onions are low in nutrients but are valued for their flavour. Most whole onions are slightly dried before marketing, making their skins dry and paper-thin. Leading world producers of dry onions include China, India, the United States, Russia, Japan, and Turkey. Spain is the leading European producer.

Onions are also available in various processed forms. Boiled and pickled onions are packed in cans or jars. Frozen onions are available chopped or whole, and bottled onion juice is sold for use as a flavouring.

Dehydrated onion products have been available since the 1930s. Processing involves elimination of most of the moisture by heat or by freeze-drying. Such products include granulated, ground, minced, chopped, and sliced forms. Onion powder is made by grinding dehydrated onions and is sometimes packaged in combination with salt.

Dried onion products are used in a variety of prepared foods. They are also sold directly to the consumer for use as condiments. The United States is the world’s leading producer of dried onion products, and the state of California is a major producer of onions developed and cultivated for this industry.

1 comment:

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