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Onion
Onions 07-1-
Scientific Classification
Kingdom: Plantae
(Unranked): Angiosperms
(Unranked): Monocots
Order: Asparagales
Family: Alliaceae
Genus: Allium
Species: Allium cepa
Plant Data
Min germination temp: 13°C (55°F)
Max germination temp: 35°C (95°F)
Germination time: 14 days
Time to transplanting: +50 days
Time to harvesting: +120 days
Mature height: 45cm (17½in)
Ideal pH range: 6.0 - 7.0
Sow depth: 2.5cm (1in)
Sow spacing: 5cm (2in)
Hardiness Zones
Ideal Hardiness Zones
· · · 3 4 5 6 7 8 9 10 · ·

The onion (Allium cepa) is also known as the "garden onion" or "bulb" onion. Above ground, the onion shows only a single vertical shoot; the bulb grows underground, and is used for energy storage, leading to the possibility of confusion with a tuber, which it is not. Allium cepa is known only in cultivation, but related wild species occur in Central Asia.

Planner[]

From Sets[]

J F M A M J J A S O N D
Planting Time
Lifting Time

From Seed[]

J F M A M J J A S O N D
Sowing Time (Indoors)
Transplanting Time
Sowing Time (Outdoors)
Lifting Time

Growing[]

Location[]

Onions prefer a sunny, well drained site although a moist site can be tolerated if grown in ridges. Avoid bulky soil, but again this can be tolerated if conditions are managed.[1]

Soil[]

Soil should be fertile, but excessive nitrogen will delay maturity so avoid freshly manured soil.[2] Manure should be dug in 2 months prior to planting. Acidic soil should be treated with lime to neutralise its pH.[1]

Sowing[]

Sow seeds in modules in late January and kept indoors at temperatures of 13°C (55°F) to 35°C (95°F). You can plant up to 5 seeds in each module, once transplanted plants will push apart.[1] Alternatively sow seeds outdoors in February-March. For a continual supply; make a second sowing in August for a crop ready in June the following year.

Transplanting[]

Transplant seedlings in early April.

Planting Sets[]

Plant onion sets in Spring so that the tip of the bulb is just showing above the soil.

Aftercare[]

Weeding[]

Since onions do not produce dense foliage to shade the surrounding earth from weeds; regular weeding is essential or plants will soon be overrun with competing plants.

Bolting[]

Bolting can be an issue with some onions depending on variety and growing conditions. If a flower stalk begins to form, cut it off.

Harvesting[]

Onions are ready to harvest once foliage starts to turn yellow. Leaves should not be folded to speed this process up. Lay harvested onions in a warm dry place for 2 weeks to dry out. Onions that develop a thick neck should be used immediately as these do not store well and are prone to neck rot.

Storing[]

Once foliage is completely dry, store onions in a dark, cool, dry place either by packing in boxes or in plaits.[1] Onions should keep for 3-6 months depending on variety.

Troubles[]

Full troubles list: Allium troubles

References[]

  1. a b c d "Grow onions and garlic". BBC Gardening Guides. Retrieved 2010-07-17.
  2. (2004). "Dry Bulb Onions". Oregon State University. Retrieved 2010-07-17.
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Onion varieties
Red onions Electric red · Red baron
White onions
Yellow onions
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