Onion seeds are not usually difficult to grow or to collect. The only thing to keep in mind is that onions are a biennial, meaning that they seed once every two years. By growing and saving your own onion seeds, you can develop a healthy reserve of seeds for next year's garden, for eating directly, or for sprouting.


  1. Watch for flowers and then seed heads to form during the late summer of the second season.[1]
    • You may wish to plant extra plants if you want onions to eat during the first season.
  2. Most of the flowers will be dry, and the seeds will begin to fall out on their own.[2]
  3. [3]
  4. Many seeds will fall out on their own. For the rest, place them in a bag, pound the whole bag against a hard surface.[4] If you have many seeds, you may be able to use the wind to separate them from stems and other matter. Use a large bowl and toss them in the air, or pour them from one container to another in a light breeze. The wind should sift the lighter stems away and leave the heavier seeds to fall.
    • There's no harm in having a little bit of stem or seed head in your seeds unless you are sprouting them. If you plant it along with the seeds, it will just decompose.
  5. [5] [6] Label the seeds with the year you saved them, or plant them immediately in a mild climate. Most seeds work best if they are used within one year of saving them[7] — you may get an acceptable germination rate the second year, though.
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Community Q&A

  • Question
    Do the flowers need to be pollinated?
    Community Answer
    Community Answer
    Just like a woman cannot get pregnant without semen from a man, a flower normally cannot go to seed without some kind of pollination. However, this doesn't necessarily need to be done by insect pollinators. Onion flowers sit close to each other, so the wind can make some pollination happen. You can also bend the flowers toward each other when the pollen is ripe and pollinate each with the other like that. Don't worry if you don't regularly get bumblebees visiting your windowsill, though; other insects like flies and such do also pollinate plants. They're just less noticeable. If you see a flying insect on your onion flowers that isn't actively eating them, it's likely an undercover pollinator.
  • Question
    Can I save and use the seed from onions that have bolted?
    Community Answer
    Community Answer
    I tried this with an onion that had sprouted leaves in my cupboard, and my onion ended up sprouting two giant flower stalks and going to seed with no trouble. Do make sure you give it enough space - the roots don't go deep, but the whole thing gets larger than you'd expect. Get a pot with two or three inches of extra space around the onion. Leave the onion sitting up in shallow water to encourage root growth for a week or so first (I used a wide glass so the sides of the glass prevented it from falling over). You can just sit the onion on top of the soil with the bottom a bit buried.
  • Question
    How many onion seeds are there in an average flower?
    Community Answer
    Community Answer
    There are 42 onion seeds in the average flower. Most of them are in the roots.

Things You'll Need

  • Garden snips, secateurs, or similar device for plant cutting
  • Container to catch seeds
  • Bag to keep seeds


  1. https://saltinmycoffee.com/how-to-save-onion-seeds/
  2. https://saltinmycoffee.com/how-to-save-onion-seeds/
  3. https://www.theartofdoingstuff.com/saving-onion-seeds/
  4. https://www.motherearthnews.com/organic-gardening/gardening-techniques/onion-seeds-ze0z1510zbay
  5. https://www.motherearthnews.com/organic-gardening/gardening-techniques/onion-seeds-ze0z1510zbay
  6. Olivia Choong. Plant & Gardening Specialist. Expert Interview. 3 September 2021.
  7. Olivia Choong. Plant & Gardening Specialist. Expert Interview. 3 September 2021.
  8. Olivia Choong. Plant & Gardening Specialist. Expert Interview. 3 September 2021.

About This Article

Olivia Choong
Co-authored by:
Plant & Gardening Specialist
This article was co-authored by Olivia Choong and by wikiHow staff writer, Janice Tieperman. Olivia Choong is a Plant and Gardening Specialist and the Owner of The Tender Gardener. With more than six years of experience, she specializes in gardening, permaculture, and self-sufficient and low-impact living practices. Her work has been featured in media outlets such as The Straits Times and Channel NewsAsia (CNA). Olivia holds a Bachelor of Mass Communications in PR and Journalism from Murdoch University. This article has been viewed 446,776 times.
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Co-authors: 13
Updated: January 11, 2023
Views: 446,776