What causes onions to bolt? Can this be stopped? Is the ground too hot? cold? wet? dry?

Any ideas appreciated



  • Probably too dry, but will eventually go to seed anyway. When they do that there probably isn't much more growth to come so you can start to lift and enjoy. Usually you lift the plant a bit to break the roots, lay it down to enable the foliage to die off (which also feeds the bulb) , and then store or eat. Plants that go to seed store less well, than those that don't. So if you do store check them regularly looking for mould or nasty things. Then salvage what you can.image

  • John17John17 Posts: 19

    Thanks Woodgreen. I think you are assuming that the onions are mature, but they are still very small. I am surprised that this one has bolted so early.I have kept them quite well watered in my raised bed so I doubt they were too dry. Should I lift them as soon as they bolt even if very young?

  • ItalophileItalophile Posts: 1,730

    Onions have to be the most neurotic veg on the planet. The only need the slightest disturbance to think they're in peril and will seek to reproduce themselves by producing a flower, which is what bolting is all about. Fluctuating temps can be enough to do it. I now wait till temps have stablised before planting them.

  • John17John17 Posts: 19

    Thanks Italophile. So I could wait a long time in the NE of Scotland for temperatures to stabilise!!

  • biofreakbiofreak Posts: 741

    I've tried everything and they still bolt!! I just live in hopes and eat BIG spring onions!!!

  • ItalophileItalophile Posts: 1,730

    John, fluctuating temps can be one cause. Or too cold or too hot. Or irregular watering. Anything that gives them a fright. They're just neurotic creatures.

  • I have only just managed to finish my raised bed and have been growing my onions in my conservatory.

    How deep should I plant them ?   

  • ItalophileItalophile Posts: 1,730

    I plant them deep enough just to bury the white part.

  • Thank you. I am going to do it now while the rain holds off !

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