Onions GroMór


Onions are a popular vegetables to grow at home as they are used continuously in the kitchen. Bulb onions store well and it is possible to have them from your own garden from mid-summer to the following spring. They are relatively easy to grow, not needing a great deal of effort, and a good crop of onions is a very satisfying achievement. Onions come in a wide variety of shapes, sizes and colours. 

Soil Preparation

Onions have a relatively short growing season, at least if sown in spring, and they need good soil in a sunny position to grow quickly and make good size before bulbing up begins. The soil must be fertile but not too rich. Very rich soil with a lot of organic matter tends to make the plants very leafy, large and with a greater number of ‘thick-necks’, which do not store well. Ideally onions can follow a crop such as potatoes or courgettes fro which lots of organic material is applied. 


You can pull onions at any size throughout the season but you will know that your onions have actually stopped growing and are ready for harvest and storage once some of the leafy stalks begin to turn yellow and lie down. The general rule of thumb is to wait for half of the plants to fall over, and then harvest the entire planting. This is the scenario in a dry summer, but often the case in Ireland is that of relentless rain, so leave stay green and fail to die back. If you are happy with the size of your onions, you could try to accelerate ripening by pulling the onion bulbs slightly to break the roots and then pull them completely about two weeks later. 

Top tips

  • Onion bulbs can be loosened in the ground with a fork to trigger bulb ripening
  • To improve storage quality, place newly picked onions on a paved area or a wire rack to dry
  • The number of leaves the plant produces before the days get shorter determines the size of the onion – therefore the earlier you plant the seed the bigger the onions will grow


Thick-necks: a phenomenon caused by overly rich soil, possibly too much organic material in nitrogen – they will not keep well. 


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