How to save onion seeds from the garden

In the past I have harvested seeds for cilantro which worked so well I have decided to try more this year. Now my gigantic onions are producing seed stalks and umbels are beginning to open seems like a good time to try harvesting my own onion seeds.

To save these seeds it is pretty simple, when the umbels have dried out and begin to open. At this time carefully cut them off (making sure that seeds do not fall) and place in a them in a cool dry location for 2-3 weeks. I prefer to put my harvest seeds in the refrigerator in a paper bag. It is a good idea for onions to cross pollinate so I will plan on buying some other onion seeds to mix with the ones I am harvesting to allow for cross pollination.

Onions take 100-120 days from seed to maturity, if you start from sets which you grow from the previous year can shave 3-4 weeks off that time. I could make my own onion sets by planting 30-40 seeds in a square foot area during late summer. After two months rake over the tops and let them turn brown and dry out then store them in a dry place until next spring.

My PC grow box will be empty 10 weeks before my last frost date so planning on starting my onion seeds in there moving them outside 4 weeks before the last frost.

If you want to learn more about saving seeds for onions or other vegetables be sure to check out International Seed Saving Institute which has great advice about saving seeds from dozens of different plants.

9 Responses to “How to save onion seeds from the garden”

  1. Nancy J. Bond Says:

    I’ve always enjoyed the challenge of growing things from seed — good luck with your onions.


  2. Persa Says:

    So at this stage in the picture is when you cut it off??


  3. Jason Says:

    I'm not sure, but I cut mine once the pod open's, revelas flowers, and then gets pollinated. Once pollinated by bees, the indicudual flowers close back up and form seeds. However, this is my first time harvesting "onion: seeds.


  4. Jason Says:

    Here is some additonal info I found that may help regardign when to clip your umbels.HARVEST: Clip umbels as soon as majority of flowers have dried. Seeds will start dropping from some flowers at this time so check often. Allow to dry in cool, dry location for up to 2-3 weeks.


  5. Trevor Says:

    Can normal Onion seed be used as a seasoning or spice?


  6. The Cheap Vegetable Gardener Says:

    I was curious and did a quick look and appears that you can use onion seeds as spices (I personally have not tried it)


  7. lost and confused Says:

    If you plant your onion seeds in winter time around october or november.Can you still leave it for about 2 months then bend over leaves and make sets that way???


  8. Marc Says:

    To Persa: No, the stage shown in the photo above is when the flower ball is just beginning to open. A few days after that picture the flowers will open and several weeks after the flowers have opened the center portion of each flower will grow into a triangular “ball”. This ‘ball’ contains the seeds, but the ‘ball’ needs another few weeks to dry out so the seeds harden. Once the seeds dry out and harden the triangular ‘balls’ will start to open and drop the seeds. So you want to catch that just-right moment when the ‘balls’ have dried but have not started to open up. That’s when you want to clip off the flower ball that now has a hundred or more of the seed ‘balls’ so that you can put the flower ball into a paper bag so the seeds can fall out and be captured in the paper bag. I wish there was a way for me to post a picture from my garden. My onions are at that stage where the seed balls are still green and I’m now waiting for them to start drying out.


  9. Coral shaw Says:

    I live in northern New Zealand and we are in middle of winter. I have a spring onion seed ball ready to burst into bloom but is getting soaked with all the winter rain. Should I cut it and dry off inside??


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