Garden Action

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Growing Onions

Easy to grow with a long storage life, onions are one of the best vegetables for the home gardener.

They have the advantage of being a sensible proposition in both the large and small garden, and can be grown in the same position for several years. With a little planning, they can be available for nearly all year round eating.


Latin Name
Allium cepa

Edible bulb vegetable

Site and Soil
Full sun on most soils.

Plant to Harvest Time
Spring onions 11 weeks
Onion from seed 24 weeks
Onion from sets 20 weeks
Japanese onions 46 weeks

How Many?
Spring onions 60 per 1m (3ft) row
Onion 7 per 1m (3ft) row

The introduction of heat treated onion sets (small onion bulbs pre-started into growth before sale) now means that growing onions is almost fool-proof. 

Where To Grow Onions
Picture of Onion Variety 'Red Delicious'Onions prefer a a sunny position with a rich but light soil, however they will do well in most soils as long as it is firm. For this reason it is best to prepare the soil well in advance of planting - December time is fine for maincrop onions, June is best for Japanese onions. Dig the soil to 45cm (18in) deep, working in any organic matter available - remove any stones in the soil that you come across during the digging. Just before planting, tread the soil down so that it is firm.

Onions are ideal plants for growing in small confined spaces, they particularly thrive in raised beds. For more information click here to go to our page on raised beds.

When To Plant Onions
Onions should be treated differently according to their type. Each is described below.

Maincrop onion seed and sets (small, part grown onion bulbs) should be sown outside starting March. If they are sown under cloche protection, they can be sown four weeks earlier.

Japanese onion seed should be sown outside in mid-August.

Spring (or salad) onion seed should be sown at three week intervals from early April to early June.



Name: jim@GardenAction
Date posted: December 10, 2011 - 11:49 pm
Message: It may be that they need time to mature if grown from seed, depending on when they were planted. Leave them in the ground until later in the season.

Name: .Bev
Date posted: December 10, 2011 - 09:00 pm
Message: could you please tell me why my red onions have grown like a large spring onion , they have not formed a bulb, they are very healthy and lush looking we have good soil we dug in sheep pellets and compost plenty of sun so not sure why this is happening.


Name: jim@GardenAction
Date posted: November 18, 2011 - 04:33 pm
Message: Follow the excellent advice given on these pages;

Name: Shedrick John Zoryou
Date posted: November 18, 2011 - 08:07 am
Message: Hello there! I live in Liberia, West Africa; We do import onions...and have a market for it here! I would like to grow onions on a very large scale; we have rains from mid April to mid October...kindly advice me on what to do and how to begin... the type of onions, etc.

Name: Annan Machege
Date posted: November 18, 2011 - 07:36 am
Message: I am in Tanzania East Africa, would like to grow onions on large scale please advice me what type of seeds I should plant, time, procedure on how start and to follow for a better returns. We have rains starting from November through December and March through April.

I m South Sudanese small scale farmer I need to start growing onions, so I ask for your advice

Name: jim@GardenAction
Date posted: November 13, 2011 - 12:26 am
Message: Roots are underground and some of the bulb.

Name: lola
Date posted: November 12, 2011 - 04:45 pm
Message: do onions grow underground because there are little white things on my onion plants and i don't know what that is

Name: jim@GardenAction
Date posted: November 10, 2011 - 04:18 pm
Message: Try the advice on this page: As to commerce, we cannot advise.

Name: judy nduta
Date posted: November 10, 2011 - 10:53 am
Message: i would want to start planting onions in eldoret town.kindly advise on how to go about it and also advise on the marketing aspect.

Name: jim powell
E-mail: Private
Date posted: October 17, 2011 - 03:50 am
Message: You were given good information. From your description, your onions and leeks appear to be affected by onion fly. Both onions and leeks belong to the allium family and are affected by the same pests. In the bad old old days, you would use an organophosphate pesticide but we are more enlightened these days. What you did was the right thing, dig them up. Burn, do not compost them, and grow yur onions in another part of the garden to prevent carry-over of the pest into next season.

Name: john adams
Date posted: October 15, 2011 - 01:40 am
Message: For the last 2 years I have grown onion sets on my allotment, once the leaves are about 9-12 inches tall they start to go crinkly and fall over some of the leaves go yellow and the onion stop growing
on lifting the bulb and stipping the outer leaves off the bulb has white maggots in the baulb also the brown caster. I am told it is onion fly.
How do I stop this happening, I have lifted all onions and burned the baulbs .
I have today 13/10/11 checked my wintering leeks and found the same problem both maggot and caster ,have now lost both onion and leek crop for last two years.

Name: ashraf
E-mail: Private
Date posted: October 02, 2011 - 01:51 pm
Message: I,am in Egypt I want to pre emergance herbicide for anuual broad leafon onion

Name: isaac
E-mail: Private
Date posted: September 27, 2011 - 07:52 am
Message: I'm in Africa Malawi I want to grow onions on a large scale so I wanted advice for type of seed n planting time coz we usually receive our rains late November

Name: John
Date posted: September 26, 2011 - 01:22 am
Message: I'm looking for a good red onion to put in my garden. I want one that is sweet and will grow large along with my 1015 onions. I normal plant in Nov. and have large onions in may

Name: Lemi
E-mail: Private
Date posted: September 18, 2011 - 12:53 pm
Message: I m South Sudanese small scale farmer I need to start growing onions, so I ask for your advice on how ton start and procedure
to follow for a better returns.

Name: alan
Date posted: September 17, 2011 - 01:02 pm
Message: what would you consider a good type
of onion for growing through the winter
on a allotment.

Name: ken carman
Date posted: September 09, 2011 - 11:07 am
Message: Whats the best type of onion to produce the largest single onion?

Name: rto
E-mail: Private
Date posted: August 20, 2011 - 12:48 am
Message: thus onion and garlic will grow in a hydroponics setting.. tnx

E-mail: Private
Date posted: August 08, 2011 - 06:09 pm
Message: I live in the Eastern Region of Ghana and I want to start the production of onion soon. Can you please advise me on proper cultural practices involed ton ensure a good yeild. Thanks.

E-mail: Private
Date posted: July 29, 2011 - 03:08 am
Message: i wan to know about the onion n Garlic crop.