Growing Onion Seed


I’ve been growing and planting my own onion seed for 3 or four years now (with an additional planting of new commercial OP seed as well) and just harvested this year’s “crop”. Noticed something different this year. The replanted onions grew great and flowered, however most of the flowerettes did not produce seed, maybe around 10%. One other odd thing is most of these flower heads also produced tiny onions, like an egyptian or walking onion.

I am curious if there are any other onion seed growers out there, and if anyone knows what might cause an onion to favor “sets” vs seed.

I will plant the “sets” just to see what they produce, but it seems a bit odd.


Curious how many onions did you plant for seed? I’m planning to do this next year and some sources say only 3 are needed but The Manual of Seed Saving recommends 15-20 onions to supply sufficient genetics (?) for strong seed.

Also curious if you had other allium varieties flowering at the same time since alliums are outcrossers.


I generally plant 3-4 onions (the best of the previous year’s crop). I don’t believe there are any wild or other alliums nearby, this is a pretty harsh climate and wild onion is not native AFAIK; And these seed onions are grown second year in the greenhouse (because our season is short enough that seed may not mature outside), so very unlikely they got any “wild pollen”.)

Good thoughts, but I was thinking it might have been something in how I grew them out that caused this, but too small a genetic pool might be an issue.


Hi Steve, I’ve been growing my own seed since 1995 from whatever early op varieties that were available back then so I have a mix, though now my line is likely narrower since I’ve been selecting what I like best over those years. I grow them outside but do have trouble getting a good crop of seed with the short season some years, which is dicey since the seed doesn’t last only 2-3 years. I plant them in the fall, 6-8 of the best bulbs, mulched well. I did once have them both flower and set bubils, back in 2001. I think that was the only time and my notes just state my surprise and that it was a good seed year anyway. I doubt that I did anything different than usual. I didn’t plant the bulbils but now wish I had. It’ll be interesting to see how yours grow. Since the seed planted from that year was true to type following years it most likely wasn’t due to crossing with something else (as with yours, I didn’t have anything for it to cross with anyway). I don’t know the scientific reason but it’s the kind of thing that keeps me saving my own seed all these decades. Sometimes nature gives you a fun surprise! Sue