Saving Onion Seeds – So You Can Smell Like a Chef.

Being a lazy gardener is sometimes how you become a productive one as well. Because sometimes *not* doing things – is how you do things in the garden. Too lazy to pull last year’s bolted onions, lettuce or kale? Excellent. Because not doing that is how you’ll get lettuce, kale or onion seeds this year.

If you have a garden and you’re growing something that comes fully packaged with seeds inside of it like a tomato or a cucumber it’s pretty obvious how to collect them.  But then there are mystical seeds like radish, onion or kale seeds.

Where do THOSE come from? I mean where the hell are they?

Well, they’re in the flowers. But to get to the flowers you have to let your plant “go to seed”. Which literally means letting your plant flower and form seeds before you unceremoniously rip it out of the ground during garden cleanup.

How to Save Onion Seeds

How to Save Onion Seeds

Active Time: 15 minutes
Total Time: 15 minutes
Estimated Cost: $0

How to save onion seeds no matter where you live.


  1. Allow your plant to "bolt" and flower. Onions have a tendency to do this if there's a heatwave.
  2. Let the flowers form. During the end of the flower's life the plant will start to form seeds.
  3. Check to see if the seeds have dried. They'll go from green (usually) to brown or black when they're ready to harvest.
  4. You can also harvest the flower heads just prior to the seeds drying out by cutting the flower stalk. Hang them upside down with a paper bag tied around the neck of the stalk, over the flower. As the seeds dry they'll drop into the paper bag.


  • Almost any vegetable you grow that doesn't have a seed inside it can be allowed to flower and go to seed for collecting.
  • Radish, lettuce, kale, chard and onions are a few examples of seeds you can save this way.
  • If the plant you're saving seeds from is an heirloom variety (not a hybrid) then you'll get an exact replica of what you planted originally from the seed.
  • If you save the seeds from a hybrid you'll still have useable seeds but they won't match the parent plant exactly. They might be bigger, or stronger, or even a different colour.

If you were lazy enough to leave a few things in the ground over winter chances are they’ve flowered for you. Now all you have to do is harvest the seeds.

how to save onion seeds

In the past I’ve shown you how to save tomato seeds.  I’ve also shown you how to save lettuce seeds.  Saving onion seeds is slightly different because onions are a biennial.

saving onion seeds


A quick explanation of seed saving:

Annual, Biennial & Perennial Vegetables.


There are 3 different types of plants:  annuals, biennials and perennials.

Annuals:  Plants that germinate, flower, produce seeds and fruit in a single season.  Then they die.

Examples of annuals in the vegetable garden:  Tomatoes, Squash, Cucumbers, Beans, Peas, Melons, Peppers, Potatoes.

Biennials:  Plants that produce fruit in a single season but don’t flower (which is where the seeds come from) until their second year.

Examples of biennials in the vegetable garden: Kale, Swiss Chard, Onions, Broccoli, Beets, Rutabaga. 

Perennials:  Plants that go through the entire cycle of producing and flowering every year, over and over for many seasons.

Examples of perennials in the vegetable garden:  Raspberries, Strawberries, Rhubarb, Asparagus.

A simple way to identify a plant as either annual or biennial is if the vegetable contains seeds right in the actual vegetable it’s an annual.  If there is no seed in the vegetable then it’s a biennial.

Also if every year you go outside and there’s that stupid plant again even though you wish you could kill it, … then it’s a perennial.

This isn’t true all the time and there are exceptions but it’s a good rule of thumb to go by.


saving biennial onion seeds

So how do you save the seeds from a biennial?  What zone you live in will dictate how you do it.  If you live in a  zone where the cold doesn’t kill your plants, you simply leave a few of your chosen biennials in the ground.  In the spring they’ll start to grow again, sending up a shoot with a flower on top.

That was the case with these green (spring) onions I left in the ground last year.

Other plants like swiss chard or beets may get killed by the cold so saving those seeds is a bit different.  I’ll get into how to save beet and carrot seeds in another post but basically since these types of plants aren’t thrilled about surviving the winter outside you either need to protect them outside so they can continue to grow and flower in the spring, OR you can bring them into a cool room in your house (or garage) and replant them in the spring! 

Onions will survive the winter in my zone of 6b.  So getting them to flower is just a matter of leaving them in the ground and remembering not to pull them in up the spring when you wonder what the hell this weird onion is doing in the middle of your garden.

Anywhere from May to July (depending on the variety and your gardening zone) the onion will send up a shoot with a big pretty flower on the top.  Just let it keep growing.  Eventually tiny seeds will form. When the seeds have formed cut the flower stalk and allow the flower to dry.  Once it does you can just shake the seeds out.

If you want to plant immediately you can also hand pick the seeds out of each tiny, individual flower.

The reason I cut the stalk off and let it dry on my porch is so I don’t lose all of the seeds.  If it dries in the garden all the seeds will drop into the soil.

A quick guide to saving onion seeds

I harvested these seeds in June and planted them in early July for a late supply of green onions.  And yes, I’ll be leaving a couple of them in the ground so next year I can harvest more seeds and do the same thing over and over again year after year.  I’m a perennial gardener.

If Martha Stewart, Gordon Ramsay, Hester Blumenthal, and Anthony Bourdain (RIP)  all announced they were going to show up at your house at the same time here’s what you need to do.  Fry some onions.  Maybe first you should make sure your phone is charged and Instagram updated, but then you should definitely fry some onions.

Nothing makes a kitchen smell like the cook knows what they’re doing like the smell of fried onions.  Baked cookies are fine for an open house, but if actual chef-like smells are what you’re trying to put out in the world, nothing tops a fried onion.  Lay a random weird ingredient like squid ink or dry ice on your counter and Martha, Gordon, Hester and Anthony will automatically give you chef status. You don’t even need to use the squid ink.  Just have it visible.  

Grow your own onions for cooking and they’ll be begging you to cook in their kitchens.  Save the seeds from your onions and grow them over and over year after year and tell them all about how you do it?  They’ll be asking you for cooking lessons.  ‘Cause you’ll seem JUST that smart, JUST that authoritative, JUST that committed to the world of food.

Even though in reality all you are is a person who couldn’t be bothered to completely clean up the garden last fall because it was fall and you were ready to hang up your gardening gloves and pick up the television remote.

One final tip before I go … don’t let Martha and Gordon sit beside each other at dinner.  Just trust me on that one.

Saving Onion Seeds - So You Can Smell Like a Chef.


  1. Elizabeth says:

    Channeling my inner librarian here, as I found an actual error in your post (sorry).
    I agree with 99.9%, but encountered a YouTube video last year that encouraged me to overwinter pepper plants inside (not wonderful) and to plant them for a second year.
    Hurray, it worked. My peppers are poblanos, tiny, shiny and perfect!

  2. I have a new garden my neighbors helped me build last year. All I grew was tomatoes but this year I have a volunteer tomato, tomatoes, peppers, spinach, lettuce, peas and 4 herbs. So excited that everything is doing well. Oh! Except the cucumber, I forget about it because it’s right by the tomatoes. I have a cage for it and hope it can be trained up. If it grows more than 6″.
    But anyways… I will have to revisit your garlic posts and get some onions in too. Can I put them in in the fall? I need to make room in the other half of the garden. It’s still all daisies and bare spots . Tried growing echinacea from seed but nothing is happening. That will be my new garlic and onion spot.
    p.s. a guy friend told me his trick for remembering the difference between plants. P is for Perrenial and P is for Permanent. Perennials are Permanent!

  3. Hydrotilling says:

    Duplication is the reason for it just like any buddy that raises any animals you don’t kill off everything expected to regenerate the next year ….fertility , Expansion , Control, is art job titles being a farmer or Gardner to be able to keep food on the tables

  4. Leslie says:

    Timely post for me! I had 3 onions bolt and those lovely stalks and flowers came up. I cut two for decoration! They looked so much like the ‘floral’ alliums I’d planted in my front yard.
    They also remind me of something from Dr. Seuss. I love them. Now I’ll see if the one left in the garden goes to seed and I can collect them.

  5. Melinda says:

    Yeah I have one of those darn perennial plants. Yes Ive tried to kill it many times. My husband even sprayed the entire bed with Round Up. Still going strong.

    It was my daughter’s idea to plant arugula one year. (I hate the stuff) Then she lost interest in her garden and now we have more arugula than any family could ever eat!

    So if anyone has any ideas I haven’t tried….

    • Emily says:

      I am not an arugula person, either, but it’s fairly tasty sprinkled over pizza. It also makes homemade pepperoni pizza seem really fancy, like from a boutique pizzeria.

  6. Michelle says:

    Karen your post is very timely. I will be leaving my onion seed heads for a while amd I think I will lose them before I get back. Can I really just cut the stem and hang them upside down in the garage and they will be dry out and will they be VIABLE seeds to replant if they didn’t go to dry naturally? Have you replanted ones done this way?
    Michelle. PS. I so enjoy reading your work. You are a great writer.

  7. Jane says:

    Funny that I’m reading this now. Late last fall, I moved the green onion to the raised bed where Swiss chard were growing and covered everything with layers of floating row cover. Somehow, everything overwintered well. Then in the spring, I planted some kitchen scraps – different types of cabbage and lettuce – in the same bed and see how they’d grow. Now everything has bolted and are going to seed in that bed. Think I’ll just let the bed be and cover it with row cover again late this fall. Maybe I’ll have onion and greens next year without having to do any work.

  8. Beth Bilous says:

    Oh what a fool I am. When my chives sent up gorgeous purple flowers, or rather buds that would be flowers, I annoyingly picked them off and tossed them. I was trying ot extend the life of the damn chive. I really just was not aware that damn it girl, they are the dang seeds. UGH.

  9. Jeannette says:

    Hey Karen,
    Last year you wear going to test a solar water fountain-for bird baths-how did that turn out? Did it store energy?

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