Onions Seed seed starting

Onions – Starting from Seed is Easy and Economical

I’ve been growing onions for 34 years and they’re one of my best crops.  Took me about 3 years of gardening to find out that the best, the biggest and the healthiest onions come from transplants.  But what I didn’t find out until recent years was — how easy and economical it is to start the seed and grow your own transplants.

It’ll cost you about a penny a piece ( or less) to find out for yourself.

Great for either the Winter Sown Method or Indoors

Growing onions from seed is a piece of cake!

I started six varieties of onions on December 25th via the  winter sown method. Even though the ‘soil’ in the jugs has been frozen solid off and on since then, my guess is that the sun warmed it long enough for almost all the seed to germinate.

If you start indoors with warmer soil temperatures your germination will be quicker — sometimes only 4 days.  My winter sown onion seed took about 2 weeks to germinate.  Had the temperatures been even colder, I may still have been waiting.

But, they’re up and growing beautifully. Once they get into my garden with its good drainage, full sun and lots of organic matter they’re gonna make great onions.

When to Start Your Onions 

Allow at least a week for germination, 8 weeks growth before transplanting and anywhere from 12 to 18 weeks of growth in the garden.


The idea is to plant in time for the onions to get as much top growth as possible before length of daylight in the summer triggers bulbing.  When that happens —- the onion stops making the top and starts making the bulb. The longer you can have your onions growing in the ground before that happens the bigger they’ll be.

(Keep in mind that some varieties get bigger than others.  3″ could be big for one variety and 5 or 6″ could be big for another variety.)

How to Start

Follow my instructions for starting seed in my post on Seed Starting with the following differences and additions:

  • Use jugs or plastic pots that give the roots of the onions at least 4 inches of soil.
  • Just scatter densely (maybe 1/8 to 1/4 inch apart) and don’t worry too much about spacing at this time.  The roots will separate readily for transplanting.  And at this time in their life they don’t mind a bit being close together.
  • Cover with about 1/16 of an inch with medium that is already wet.  (If you cover with dry medium, it’ll be hard to get the medium wet and trying to do so will rearrange your spacing of the seed.)
  • A word of caution: If you plan to grow them indoors under florescent lights rather than move them immediately outdoors as I do, be carefully of how much light you give them.  It only takes 10 hours of light to trigger bulbing in some onions (the short day varieties). You sure don’t want that at this point or you won’t get onions.
  • If need be — give them some foliar spray like Liquid Kelp Spray. (I don’t usually do this, but might this year.)
  • Harden off your onion seedlings before planting in the garden. If you need some hardening off guidelines see my post on Hardening Off Your Seedling.

What if you don’t have enough time this year to get your onions to maturity?

Suggestion #1 – Buy a packet of seed for $1.25 or so.  Start your onions.  Grow to replanting size (about 8 weeks) and plant in the garden. The worse that can happen is you’ll have a great crop of onions a bit smaller than usual.  If you’re really late — you’ll have a crop of spring onions.  How bad can that be?!  Not to mention you’ll know what to expect next time around.

Suggestion #2 – Start seed in mid July or August.  Transplant to the garden in September for wonderful fall spring onions.  Here in Virginia I have spring onions all winter long.

Final Thought

Don’t wait thirty some years like I did before starting some onions from seeds.  It’s easy and where else could you get wonderfully delicious and healthful organic onions for a penny or two a piece?!


Additional Reading:

Growing Onions

Onion Sets – What you Need to Know to Get Better Results

How to Have Garden Onions April thru January

Hardening Off Your Seedlings

Seed Starting – It’s Easy Even with Less then Perfect Conditions

You Can Plant in December


Organic Gardening is easy, effective, efficient and it’s a lot healthier


All content including photos is copyrighted by TendingMyGarden.com.  All Rights Reserved



  • Theresa, Somehow I left onion seeds off my seed order this year. Is it too late to grow from seed now- Jan. 20? I DO have transplants coming from Dixondale, and I did plant shallot seeds, so it’s not a complete loss.

    Just wondering if I’ve missed the boat for seeds as you got yours going a month earlier.

  • Sandra, I would go ahead and try at least some. I started onion seed VERY late last year. Some in late February and March. (It was a first for me — other than bunching onions.) It was too late to get really good growth from the transplants —- BUT — I am still get big wonderful delicious spring onions from those plants! So that’s about the worse that can happen.

    I would order, get them in hand, and start them the day you get them. They should take about 10 days to germinate based on what mine did this year.
    Good luck. I think you have a good chance of them doing very well. They will just stay in the garden a bit longer than your other transplants from Dixondale.


  • Theresa, I have been jotting little notes about a lot of what you have posted, but there is so much to learn that I cannot write it all down. I know that your site is under copyright, so do you allow the printing of some articles by people such as myself that just need the info for gardening? I’m sorry to ask; it’s just so much that I need to know.

  • Laura, thank you for your consideration and thoughtfulness in asking about the copyright.
    It is perfectly alright for you to print out a post for your own instruction. That way you can review it again and again even when you are not
    at your computer.
    Thank you again for asking.

  • Thank you so much, Theresa, for allowing me to print off various articles. My poor cramped hand thanks you, too:-) I am excited about beginning my garden anew and am hoping for a good harvest.

  • Thank you Theresa for your MANY onion articles! I grew plants successfully last year, in Zone 4 garden in Minnesota. This year I am going to try with seeds….fingers crossed! I wonder if you have had any success with those walking onions, aka perennial onions? I am going to be up all night reading TMG…..

  • Hi Cheryl,
    I grew walking onions so many years ago I can’t remember much about them, except that they don’t give me enough return on investment of time.

    I do grow the multiplier onions in the winter. They literally multiply 4 to 8 what you plant. AND the onions will keep as long as 1 1/2 years if necessary!

    Have fun reading tonight!

  • You mentioned starting seeds in July. This would be fun to try.
    What kind do you find best for summer seeds? Long day, short day, day neutral… (zone 6) Does it make a difference?
    Thank you

  • Gordon, I don’t really think day length would make any difference as far as the seed germinating in July. The thing that will make a difference is temperature. Optimum percentage of germination for current seed is about 68 degrees although you’ll still get about 91% germination even at 86 degrees. You might want to start them inside if temperatures are too hot, just to be on the safe side.
    Good luck!

Leave a Comment