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Last edited on March 14, 2020. View history

white onion White Onion

No scientific name recorded

A variety of onion

How to sow white onion: Direct seed indoors or plant sets (small bulbs) outside.

Sun requirement for white onion: Plant in Full Sun

White onions are a type of onion with white skin and white flesh. They are members of the Allium family along with garlic and leeks. They tend to have a sharper, more pungent flavor than yellow onions, and thinner, papery skin. They can be eaten cooked or raw (mince and add to salsas and chutneys). Make sure to choose a variety suited to your day length.

5
plantings
1
harvest
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seed packets
Growstuff is a free, community-run site for people who grow food. Keep track of what you plant and harvest, find seeds to swap, and see what is growing near you. Join to record your own white onions.

White onion facts

Lifespan

Annual living and reproducing in a single year or less
22 weeks median lifespan
First harvest expected 22 weeks after planting

Height × spread

60cm × 13cm

Row Spacing

10cm

Grown for

bulb harvested 1 time
Optimal temperature 12–25 °C
Absolute temperature 4–30 °C
FAO EcoCrop
Optimal rainfall 350–600 mm/year
Absolute rainfall 300–2800 mm/year
FAO EcoCrop
Optimal soil pH 6–7
Absolute soil pH 4.3–8.3
FAO EcoCrop

Crop cycle

85–175 days
FAO EcoCrop

Max altitude

2000 m
FAO EcoCrop

Optimal light

clear skies
FAO EcoCrop
What are growing degree days?

A plant grows with warmth, not with days. A growing degree day is one day's worth of useful warmth: how many degrees the day's average temperature is above the lowest temperature the crop grows at. Add them up from planting and you know how far along the crop is, whatever the calendar says.

Say that lowest temperature is 10°C. A day averaging 17°C gives 7 growing degree days. A day averaging 8°C gives none, as it is too cold for the crop to grow. That is why the same lettuce takes about 50 days in a summer and 90 in an autumn: it needs the same total warmth either way.

For white onion, the FAO EcoCrop database gives a lowest growing temperature of 4°C and a shortest growing cycle of 85 days at its best temperature, about 1233 growing degree days to a first harvest.

Where you've told us where your garden is, we use this and the weather there to predict when your white onion will be ready to harvest. We don't use it for how long a plant lives or when it finishes: we go by what members have logged for that.

Growing white onions

  1. Sow seeds in trays 8 weeks before planting out
  2. Dig compost into the bed 1 week before planting out
  3. Water regularly at planting out every week
  4. Weed around the plants 2 weeks after planting out every 2 weeks
  5. Feed with a nitrogen fertiliser 4 weeks after planting out every month
  6. Stop watering as the tops fall over 1 week before first harvest
  7. Lift the bulbs at first harvest
  8. Dry the bulbs in an airy place 1 week after first harvest

How members grow white onions

Sunniness

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Planted from

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Harvested for

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Plant white onions with

Photos

White onion plantings

2020-02-22_07-17-41
2020-02-22_07-17-41
by shiny
IMG_20191013_150557
IMG_20191013_150557
by shiny

Video

Where white onions grow

Only plantings by members who have set their locations are shown.

What people are saying about white onions

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White onion harvests

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Find white onion seeds

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Time to harvest

If sown now, expect a first harvest in about 85 to 175 days.

From the growing cycle in the FAO EcoCrop database, which is the same wherever it is grown.

Ecological requirements

Data from the FAO EcoCrop database for Allium cepa L.

Family / Taxonomy Liliopsida
Liliidae
Asparagales
Alliaceae
Life form herb
Life span biennial
Habit erect
Optimal soil depth medium (50-150 cm)
Optimal soil texture medium, organic
Optimal soil fertility moderate
Optimal soil drainage well (dry spells)
Optimal soil salinity low (<4 dS/m)
Photoperiod short day (<12 hours), neutral day (12-14 hours), long day (>14 hours)

Learn more about white onions

Resources outside Growstuff.