Growing Onion

Allium cepa : Amaryllidaceae / the onion family

Jan F M A M J J A S O N Dec
  S                    
    P P                

(Best months for growing Onion in USA - Zone 5a regions)

  • S = Plant undercover in seed trays
  • P = Sow seed
  • Easy to grow. Grow in seed trays, and plant out in 4-6 weeks. Sow seed at a depth approximately three times the diameter of the seed. Best planted at soil temperatures between 46°F and 86°F. (Show °C/cm)
  • Space plants: 2 - 4 inches apart
  • Harvest in 25-34 weeks. Allow onions to dry before storing.
  • Compatible with (can grow beside): Lemon Balm, Borage, Carrots, Beets, Silverbeet, Lettuce, Amaranth
  • Avoid growing close to: Peas, Beans

Your comments and tips

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22 Feb 18, Trevor Smith (New Zealand - temperate climate)
If I was to sow seeds in February and plant out in say May would frosts have any adverse effect on them?
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22 May 19, Mark Taylor (New Zealand - temperate climate)
Onions are hardy plants and so frost tolerant, they will survive the winter. My understanding is If you plant them in Autumn you can harvest them in spring as spring onions but you won't get bulbs. They need to be planted in the spring for them to develop into onion bulbs. This is because bulb formation only starts after the summer equinox when the days start to shorten.
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26 Feb 18, Mike (New Zealand - temperate climate)
If you sow now you would transplant in 6-8 weeks. I think onions can handle some frost. Check on the net about this.
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17 Jan 18, Joe Branco (Australia - temperate climate)
Why are brown and white onions sown at different times
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04 Dec 17, andrew heaps (New Zealand - temperate climate)
hi,my onions have thick stalks just above the onions them selves.is that normal?and if not what is the remedy?
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29 Oct 18, hamish (New Zealand - cool/mountain climate)
more than likely planted a little too deeply at start warm regards hamish
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27 Nov 17, John (Australia - temperate climate)
Hello and thanks for your time I would like to grow red onions i live in the wrstarn suburbs of Adelaide when do I plant seed thank you .
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01 Dec 17, Mike (Australia - temperate climate)
Read what it says above - it tells you.
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14 Nov 17, rob (Australia - temperate climate)
onions are going to seed . Should I pick now or wait till they brown
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20 Nov 17, Mike (Australia - cool/mountain climate)
In future pick before they seed or when you first see them starting to seed.
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Showing 181 - 190 of 371 comments
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two questions. Which variety of onions and garlic are best for growth in Puerto Rico. were can I buy them and expect to get them to Puerto Rico. Many say they are not to be shipped to Puerto Rico(price for living in the colony). Thanks, C.Foy

- Clifford Foy

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This planting guide is a general reference intended for home gardeners. We recommend that you take into account your local conditions in making planting decisions. Gardenate is not a farming or commercial advisory service. For specific advice, please contact your local plant suppliers, gardening groups, or agricultural department. The information on this site is presented in good faith, but we take no responsibility as to the accuracy of the information provided.
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