Growing Onions

Posted By On November 25, 2008 - 6 responses
Growing Onions

When growing onions it is best to grow them from sets, these are immature bulbs that have been grown especially for planting. There are several advantages over growing from seeds, onion sets are much quicker growing, they are less likely to get attacked by pests and disease and they tend not to bolt as much as seed grown onions.

Soil Preparation

Onions love to grow in good soil, it’s highly recommended that you dig compost or well rotted manure into the soil in winter before planting. Before planting the onion sets you could also add some general fertilizer to give the sets that extra boost once planted.

Sowing and Planting

Onion sets should be planted in March or April depending on your location. Plant the sets 4 inches apart in rows which are 9 inches apart. When planting you should lightly press the set into the soil making sure that the tip of the set is still showing.

After planting you may also decide to cover the onions with nets as birds tend to pull the sets up, mistaking them for worms. Just covering with a general garden net should be enough just to protect them. Of course, once the onions begin growing the net can be removed.

Looking After The Plants

Keep the plants weed free at all time, you may wish to use a special onion hoe to do this or alternatively you can do this by hand, either way is fine.

If you decided not to net the sets after planting you will have to push the onion sets that have been pulled up by birds back into the soil. Don’t worry about this, once the onions have been growing for a few weeks and start rooting this will no longer be a problem.


The onions are mature once the stems of the plants turn brown and fall over. You should leave the plants outdoors to dry once you have harvested them. This will take 7-10 days depending on the size of the onions as well as the current temperature.

Any onions that have a thick neck should be used in the kitchen first as these will not store and onions that are soft or smell bad should be discarded.

Onions should be stored in trays or net bags in a cool, dry, frost free place away from direct sunlight and you will find that they will keep for up to nine months. Japanese onions will not store and need to be used in a month.

6 Comments Below to “Growing Onions”

  1. Paul Bishop on

    When storing, what do you class as the ‘Correct Temperature?’

  2. Lesley on

    Hi Paul, thanks for your comment. I have edited my article!! Onions need to be stored in a cool, dry, frost free place away from direct sunlight. Some people store onions in a shed or garage but one year I lost a very large string of onions that were hanging from the garage rafters during a bad winter.

  3. Vic Bethell on

    Hi, Lesley.
    Firstly may I say that I found your website very helpful. In view of the relatively mild winters that we’re getting I’m thinking of planting onion sets in the autumn with the hope of getting a spring crop. What do you think? Also, if this is possible do you have any recommendations as to onion type?

  4. Lesley on

    Hi Vic, I have had great success with autumn planted onion sets but they are ready to start harvesting after the spring crop needs to be planted so you do need the extra growing space on your plot. Autumn planted onions do not store well so I begin to pull the onions for immediate use as soon as they are a good size. Harvest time is generally around May / June. My favourite varieties are Radar which is a white fleshed onion and Electric a red fleshed onion.

  5. Vic Bethell on

    Many thanks for advice. Very helpful.

  6. Debbie Bell on

    I have grown onion sets for the last two years, although they taste wonderfull, they always have an inverted bottom, and they seem to split into parts and I end up with more skin than onion hope you can help Debbie

Leave A Comment