Onion (Allium cepa L.)

The onion (Allium cepa) is thought by some authorities to have been one of the first vegetables domesticated by humans.  Onion seeds have been found in Egyptian tombs dated to 3200 B.C. and evidence exists that onions were grown by the Sumerians as early as 2500 B.C.  Three different varieties of Allium are mentioned in the Bible including garlic, leeks, and onions.  The medicinal use of onions as a diuretic and cure for problems of the eyes, heart, and joints is mentioned in sixth century texts from India.  

   The genus Allium includes numerous vegetables including leeks (Allium porrum), garlic (Allium sativum), elephant garlic (Allium ampeloprasum var. ampeloprasum), chives (Allium schoenoprasum), shallots (Allium oschaninii), Welsh onions (Allium fistulosum L.), Chinese chives (Allium tuberosum) as well as the onion (Allium cepa L.).  Allium cepa is also known as ‘garden onion,’ ‘bulb onion,’and ‘shallot.’

The cultivated Allium family includes edible annuals, biennials, and perennials.  Several species of Allium (A. canadense and A. diabolense) can be collected in the wild and their leaves and bulbs eaten.  Perennial onions are found in catalogues under multiplier or Egyptian walking onions (cepa var.proliferum). Egyptian walking onions increase by producing new bulbs in a clump.  They send up a flower stalk that sets numerous small-sized bulbs at the top that eventually collapses from the weight of the bulb cluster.  The little bulbs take root and spread or ‘walk’ wherever they land.  These onions bulbs can be used for pickled onions or early green onions.  Allium moly are grown as ornamentals. 

   Onions eaten (especially raw) on a regular basis have a range of beneficial actions on the body and promote general health.  They are an excellent source of phytochemicals; a signigicant source of Vitamin A, calcium, iron, potassium, and fibre.  Alliums contain anti-inflammatory, anti-cholesterol, anti-cancer, and anti-oxidant components and are thought to be effective against the common cold, diabetes, heart disease, osteoporosis, oral infection, tooth decay, and other diseases.  Baked onions can be used as a poultice to remove infection from sores; fresh juice is used as a moth repellent, rubbed into the skin as an insect repellent, rubbed into the skin to promote the growth of hair and prevent baldness, is a useful treatment for bee and wasp stings, bites, and fungal skin problems; and warmed juice can be used as a drop to treat earache and aid in the formation of scar tissue to expediate the healing process.  Onions are used to heal blisters and boils in many of the undeveloped countries and products that contain onion extract are used in the treatment of topical scars in the United States.  Allium cepa is used in homeopathic medicine in the treatment of hay fever and rhinorrhea.  The juice has been used as a cosmetic to remove freckles.  The plant juice can be used as a polish for glass and copper and as a rust preventative on metals.

   Onions prefer a rich, well-drained soil with lots of compost worked in.  Plant in a sunny location as they are daylight sensitive and their bulbing is triggered by the number of daylight hours.  Choose a variety suited to the location of the garden.  Onions have shallow roots and need 1 inch (2.5 centimetres) water per week, either by rain or irrigation.  Keep them well weeded, especially after transplanting.  Seeds and sets are both available for purchase.  Seeds can be started indoors around mid-February (here in the North) and planted in the garden as soon as the soil can be worked.  Sets are immature onion bulbs that have been stored over winter and are available at garden centres. 

   Harvest storage onions when the tops fall over and begin to whither and brown.  Pull or lift the onions using a garden fork.  Dry in the sun for about 10 days, ensuring good ventilation.  The outer skins must be dry and papery before storing.  Store in a cool, dry place, and check regularly for neck rot.  In general, the more pungent varieties keep longer in storage.

   In the kitchen, onions can be eaten raw, boiled, baked, sautéed, braised, deep-fried, grilled, steamed, and pickled.  Use the bulb raw in salads, sandwich fillings, and dips.  It can be baked or boiled as a vegetable in its own right and used in flavouring soup, stew, and many other cooked dishes.  The leaves are used in salads, dips, and as a garnish.  Flowers can be used as a garnish on salads.  Onion seeds can be sprouted and have a delicious onion flavour.  All parts of the onion are edible including the flowers, leaves, root, and seeds.  Onions are easily propagated, transported, and stored.  They are available fresh, frozen, canned, and dehydrated. 

   In the garden, onion is a good companion plant for beets, cabbage, carrots, celery, cucumber, and lettuce.  Do not plant near beans or peas.  Onion plants growing in the garden repel insects and moles and a spray made from unpeeled onions and boiling water is believed to increase the resistance of other plants to diseases and parasites.  Recipe: Onion Spray. 4 cups (1 kg) unpeeled onions, chopped.  Cover with boiling water and steep for several hours.  Strain and use. 

Ideas & Options

  • To combat onion breath, recommended methods are:
    • rinse the mouth with a mixture of lemon and water;
    • eat an apple; eat several sprigs of parsley;
    • chew a citrus peel;
    • chew an aniseed or dill seed;
    • munch on roasted coffee beans;
    • suck on a piece of cinnamon or a whole clove.
  • To reduce tears when slicing onions,
    • chill or freeze the onions first;
    • cut onions under running water or submerged in a basin of water;
    • rinse and leave the onion wet while chopping;
    • use a sharp knife to reduce cell damage and the release of enzymes that irritate the eye.
  • Onion odours can be removed from the cutting board by rubbing the surface with the cut side of a lime or lemon.  A paste of baking soda and water will also work.   
  • If you have to peel a lot of onions, drop them in boiling water for a few seconds, then cool; the skins will slip right off.
  • Rub your hands with salt or vinegar to remove onion odours.
  • Don’t throw out your onions peels.  Put them in the stock pot, where they will add a pleasant colour.
  • To prepare small white onions, drop into boiling water and let them roll around for 30 seconds to a minute, and quickly place in cold water.  This loosens the outer layer so that it slips off easily.  Trim either end just a bit with a sharp knife and the outer layer will peel off without disturbing the lower layers.
  • Freeze leftover raw onions to use in cooked dishes.
  • All onions can be harvested as green onions or allowed to mature to the stage where they can be kept for winter storage.


Baked Onions

All onions can be baked in their skins.  Rub the onions with oil.  Cut a slice from the root end so that they stand-up right in the pan.  Prick with a fork to keep them from bursting, place in pan, and add liquid (broth or water) so they will not stick.  Bake at 375° (190° C) until they are done.  Onions are done when they compress when pinched.  Peel skin and serve with butter and seasonings.  Baking times are approximately: small white onions 50 – 60 minutes; medium onions 1-11/4 hours; large 11/2 hours.

Onions Baked in Foil
Peel onions and prick with a fork.  Season with soy sauce, butter, or whatever flavouring you prefer.  Wrap in foil and bake in a preheated 375° (190° C) oven or on the side of a grill.  If the onion becomes charred from grilling, remove the outer layer and eat the inner portion with butter and seasonings.

Sautéed Onions

Slice or chop onions.  Melt butter or olive oil, add onions, and cook slowly until softened and golden.