Growing Onion

Allium cepa : Amaryllidaceae / the onion family

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

(Best months for growing Onion in USA - Zone 7b regions)

  • 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
  • Red onion
  • Young brown onion

Onions come in a range of colours and shapes and sizes. Brown - strong flavour and pungent. Usually good keepers for storage. White - milder but still flavoursome. Keep fairly well. Red - Mild, suitable to use raw in salads and sandwiches. The seedlings should be allowed to gain a bit of strength before planting out - usually 4 to 6 weeks will be enough. When they are big enough to handle, you can plant out. They start off looking like blades of grass.

They don't have to be in a greenhouse (though that would be ideal), any sheltered spot will do. The idea is to guard against rapid changes of temperature, especially at night.

Onions can be bought as young plants (sets or seedlings) from garden shops/nurseries to plant straight into garden beds. Choose your variety according to your climate and the time of year as some onions will grow better in the cooler months .

Onion bulbs should sit on the surface of the soil. Do not cover. They will take six to eight months to mature. Onions are ready when the tops start to dry and fall over. Pull them and leave to dry for a few days. Store in a cool, dry airy place. Use a net bag or make a string by weaving the tops together.

Culinary hints - cooking and eating Onion

Brown onions roasted whole with other vegetables are delicious.
Red onions add colour to salads or stir-fry.

Your comments and tips

Post a comment or question Display Newest first | Oldest first, Show comments for USA | for all countries
24 Oct 24, ESTHER C BROWN (USA - Zone 7b climate)
CAN I PLANT ONION SEEDS NOW/ OCTOBER IN A 4X4 GARDEN BOX TO OVER WINTER/ ZONE 7B NY
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20 Jun 24, Nicole Hofstetter (USA - Zone 7a climate)
I wanted to try to grow big texas sweet onions Can I grow them in a container (1 plant in a container) ?
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23 Jun 24, (USA - Zone 9a climate)
Should be ok. Would probably need 1 sq ft per onion plant.
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02 Jun 24, Karen Ventura (USA - Zone 8a climate)
what type of onions should be planted in zone 8, ie: long day, short day etc?
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27 Jun 24, Laura L Ellington (USA - Zone 8a climate)
in Zone 8 intermediate and sort day onions can be grown along with bunching green salad onions.
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05 Apr 24, Cami (USA - Zone 9b climate)
any advice on best onion variety for zone 9b? I have tried texas grano but have not seen results yet (2 weeks and counting...). I live in southern california
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08 Apr 24, Celeste Archer (Canada - Zone 5a Temperate Warm Summer climate)
Since you are having problems with your Texas Grano -- I would recommend going to an Egyptian walking onion (or other walking onion). Video abojut the onion can be found here: https://www.bing.com/videos/riverview/relatedvideo?q=walking+onions&mid=17F7CAB6E4A914745E4A17F7CAB6E4A914745E4A&FORM=VIRE Additionally: the walking onion originated from a cross between the Welsh onion (Allium fistulosum), and the common onion (Allium cepa). The Egyptian walking onion, Allium x proliferum, is a member of the allium family and a great addition to the perennial vegetable garden. Egyptian onions go by many names, including tree onions, topset (or topsetting) onions, and walking onions. The seeds are slow growing, and can take several years for them to grow and flower. That’s why people grow them mostly from established bulbs. Every part of the Egyptian walking onion is edible, including the bulb in the ground, the stems, the flower, and the aerial bulbils. There are different varieties -- some zones 3-9 others 3-10. I would select a 3-10 for your area -- additionally some types grow substantial bulbs under ground -- others have small underground bulbs -- so select your variety based on your need. There are white, brown and purple walking onions. There is also the RED CATAWISSA WALKING onion -- which is not classified as an Egyptian walker -- but is still a walking onion: this variety for its larger sized bulbs and topsets that are much larger than the typical walking onion. All parts of the plant are edible. Walking onions are a standard choice for permaculture gardens and food forests -- they are very low maintenance - and very reliable -- so a good choice for anyone having difficulty growing regular onions.
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04 Mar 24, Mary (USA - Zone 8a climate)
Do onion sets do well in a container?
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07 Feb 24, Brenda (USA - Zone 5a climate)
What do you mean when you say plant out
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12 Aug 24, Vicki (USA - Zone 8a climate)
Plant out means to plant your transplants out into the garden.
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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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