Onion, Allium cepa, is a wonderful culinary and medicinal vegetable which has been cultivated for thousands of years.
FAMILY
Alliaceae (formerly Liliaceae)
OTHER NAMES
Common onion, bulb onion
PARTS USED
Bulb
HABITAT
Onions are native to the Asian steppes and are cultivated throughout the world.
BOTANICAL DESCRIPTION
Hardiness: USDA zones 3 to 9
Height: 30 cm (1 foot)
Width: 15 cm (6 inches)
Flowers: Small, green-white clustered in globes
Leaves: Thin and narrow, straight and pointed, green
Blooms: Summer months
CULTIVATION
Propagation: seeds or sets
Germination: 15-20 days at 8-20 degrees Celsius
Spacing: 5 cm (2 inches) between the seeds or 10 cm (4 inches) between the sets, and 30 cm between the rows.
Soil: Rich and well-drained. Freshly manured ground can lead to rotting.
pH: 4.5 to 8.5
Exposure: Full sun
Pests and diseases: Onion thrips, armyworms, cutworms, white rot, Fusarium wilt, iris yellow spot virus, pink root, downy mildew, purple blotch, damping-off, Stemphylium blight, basal rot/bottom rot, onion smut, black mold, seven curl disease, neck rot, sour skin, bulb cancer/skin blotch, bacterial brown rot, onion yellow dwarf virus, root-knot nematode, onion maggot
Garden Design: Like garlic, onions look good in clusters in the herb garden, around roses, and under fruit trees.
Companion planting: Onions are great companions to dill, cucumbers, garlic, marjoram, carrots, roses, lettuce, tomatoes, fruit trees. However, they hinder the development of beans, peas and cabbage. Avoid planting onions next to leeks as both plants attract the same kind of pests.
HARVEST
Onions can be harvested from July to September when the leaves turn yellow and start to topple over.
DRYING
Brush the earth off the bulb and let it dry them for two to three weeks laid out in the sun or in a well-ventilated indoor area if the weather is wet . Washing the bulbs promotes rot.
CONSTITUENTS
Sulfur rich volatile oils, vitamins c and B, potassium, peptides, flavonoids, diphenylamine
PROPERTIES
Anti-inflammatory, antibiotic, antiviral, antispasmodic, diuretic, digestive, vulnerary, cicatrizant
ENERGETICS
Hot, dry
TASTE
Pungent, spicy
SCENT
When uncut: weakly aromatic. When cut: characteristically alliaceous.
MEDICINAL USE OF ONION
Onion is an inexpensive medicinal and culinary plant used to prevent asthma attacks and colds, sooth coughs and keep the blood vessels young.
The sulfur compounds, mostly allicin, present in onions are responsible for the strong, characteristic smell and for the medicinal value of onions. The antibiotic and antiviral properties of allicin coupled with the high vitamin C content of onions, make this popular culinary herb a great preventive medicine for colds and flu. It soothes inflammation of the upper respiratory tract, relieves coughs, and eases asthma attacks.
Onions are also good for preventing blood vessel changes due to aging such as arteriosclerosis, especially when combined with garlic.
Like garlic and many culinary herbs, onions regulate the secretion of digestive juices which stimulates the appetite and improves digestion. Onions are also diuretic.
When used externally, onions promote the healing of wounds (vulnerary) and the destruction of parasites. It can soothe insect bites. However, an onion applied to the skin can also cause skin irritation and hives (urticaria).
Used internally for:
- Colds and flu
- Asthma attacks
- Coughs
- Sore throat
- Arteriosclerosis (thickening, hardening and loss of elasticity of the walls of arteries)
- Destroying microbes, worms and maggots
- Stimulating the immune system
- Improving intestinal flora
Topic application for:
- Wounds
- Inflammation of the middle ear (otitis media)
- Insect bites
Recommended daily dosage: 50 g (per German Commission E)
Expelled juice: 1 tablespoon 3 times per day
HOMEMADE PREPARATIONS
- Juice
- Powder
CULINARY USE
Onions are a very versatile kitchen ingredient and can be baked, boiled, braised, grilled, fried, roasted, sautéed, or eaten raw in salads. They can be used to season many warm dishes as well as served on their own such as French onion soup and onion rings.
SIDE EFFECTS
None known
CONTRA-INDICATIONS
People who are allergic or sensitive to onions should, obviously, not consume any onions.
References
Bühring, U. 2014. Alles über Heilpflanzen. 4th ed. Stuttgart: Haug.
Weinrich, C. 2015. Mischkultur im Hobbygarten. 4th ed. Sttuttgart: Ulmer
