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Perennial Dividing Onion Diversification

A long term project to bring back the diversity in potato onions and other perennial dividing onions by growing out seed when it is available

There's been a lamentable loss of potato onion varieties over the past century, such that old heirlooms are now incredibly hard to come by. This project hopes to help bring that diversity back.

Researcher background
I'm constantly experimenting with and trying to develop new varieties for my challenging climate. Shallots and potato onions are a favorite of my family, and I was lucky enough to have a mass flowering and great seed set in 2018. Now I need help growing out it out and evaluating the results.
Are you seeking volunteer growers or other types of volunteers?
Yes, seeking volunteer growers
How many volunteers do you need?
What will you ask volunteers to do?
Grow out potato/dividing onion seeds for multiple years and store the onions over each winter. Seed is available for purchase from the Experimental Farm Network seed store ( Or if you have your own, by all means join us and bring more diversity!
You are asked to:

Share information about the diversity and traits of your onions.

Select notable strains for keeping ability, productivity, size and/or color, and propagate these selections.

These onions do not flower and set seed regularly, if yours do, return a good portion of the seed to the project.
Is this a multi-year project?
Can volunteers expect to be able to keep some germplasm (seeds, bulbs, cuttings, spores, etc) at the close of the project?
Yes, of course
Researcher Location

United States

Project Updates

First year growing potato onions from seed

project update by
Monday, January 23, 2023 - 07:17

First time growing out true potato onion seed this past year. Seeds were from EFN and were half yellow, half white. Most of the bulbs I harvested were too small or immature and didn't cure well so have rotted. (I'm still figuring out how to grow onions successfully.) But this one still looked good and I threw it in a pot a couple weeks ago to at least ensure I could keep it alive for season #2.

From this early sprouting, it looks like 3 separate leaf sections are coming up. Am I correct in assuming that means 3 bulbs will develop this next season? This seems like it might be useful in screening for division traits... start first year bulbs inside, and if you only have one stem, yank it and eat what's not yet become baby plant food, otherwise transplant out the onions you know will divide.

green mountain po x large onion

project update by
Sunday, November 13, 2022 - 06:49

The result of growing green mountain potato onion from seed that flowered at the same time right next to a very large sized ordinary onion. Could one of them turn out to be a larger-bulbed variety? All smallish brown ones and there are more are the result of a mass sowing from seeds of 25 different accessions from a genebank.
No extraordinary differences in size came from the growout of the genebank seeds.
No huge increase in size when growing out the genebank seeds was noticed.
But an increase in size did happen with this years green mountain x large onion seed.
To be seen whether these white ones will continue to give larger onions and how they will divide.

Avid Allium Grower

project update by
Wednesday, October 26, 2022 - 01:33

Hi All,

I have been following the limited research around Potato Onions for some time now and have just re-joined the EFN conversation on this. There has been so much information online about common names that we call plants and limited information about the species that the plant may or may not be in the past, but it seems as though we have caught up a bit on the Potato Onion conversation. I first grew Potato Onions three years ago which were called Multiplier Onions to me and once I grew them out, I realized they were different. I am a huge fan of the Allium fistulosum which is my understanding of an evergreen multiplying onion as well as the different chives that are out there due to their similar growth habit. However, Potato Onions are on another level and it is my hope to begin stewarding different cultivars of this species.

I am hoping to connect with other here to acquire additional knowledge and growing considerations as I begin to build a stock of plants and seed to grow out in the upcoming 2023 season. If you have any suggestions or additional stock to share or would like to connect directly about growing Potato Onions, especially in the PNW you can email me directly at

Thank you all and hope to hear back soon!


2022 Harvest

project update by
Monday, October 3, 2022 - 11:41

Photo shows two crates showing a representative sample of my 2022 potato onion harvest. I harvested approximately 80 pounds of onions this year as well as a goodly amount of true seed. The diversity of my collection is improving at an increasing rate each year.

This 2022 growing season had a lengthy dry spell that adversely affected size of the potato onion bulbs, though general bulb quality for winter storage is excellent. Dry spells are a double edged sword, but I would take dry spells over too much seasonal rainfall any time.

On average approximately 10% of my crop flowers and produces seeds every year now. I consider this a very acceptable rate so I can get onions for planting as well as for food production and also get a decent amount of true seed to continue rapid development of the collection.

On October 01, 2022 I fall-planted approximately 450 potato onion sets for the 2023 season. I plan on planting 500-750 sets next spring as well as around 500 transplants I start indoors from true seed.

I wish this and all EFN projects were more active. These projects are the right idea but lacking in the capability for members to engage in discussion. I believe this issue will continue to cause minimal involvement and lack of interest in these potentially valuable projects.

potato onions grown from genebank accessions

project update by
Friday, August 12, 2022 - 12:35

I am just after joining the experimental farm network/ potato onion project.
My name is Philip. I live in brittany, france.
I planted about 50 potato onion bulbs grown from seed this year.
The bulbs were selected from about 300 seed grown potato onions.
The seeds came from 25 different accessions of the nordgen genebank in europe. 
They consisted of mainly scandinavian and eastern european accessions of potato onions, but also other european countries.
So all of my 50 or so plants are genetically different.
I am on a quest to try and breed potato onions that are larger.
None of these seed grown plants seem to show any extraordinary genetics in terms of size, so they don't actually interest me that much anymore.
For people, however, who want to save and even improve genetic diversity of potato onions these plants could be of great value.
Obtaining these seeds as a private person from the genebank was very difficult and expensive.
I basically selected the 50 plants out of the 300 for size and least amount of dividing (being convinced they shouldn't divide in their first year grown from seed)
This year was a very dry year and the potato onions grew very poorly.
I didn't have time to water them.
I have gone down the path of trying to cross potato onions with large size ordinary onions hoping to improve potato onion size that way.
I grew a batch of green mountain x large onion seeds this year that were all white and much bigger than the nests of the 50 bulbs i had selected from last year and that divided for the first time this year.
I will probably try and multiply all the seed grown types from the seedbanks' seed and grow them under normal conditions to better evaluate and share them.
Like I said they don't interest me that much anymore but represent a much wider genetic diversity than the handful of varieties circulating in the usa from what i know.
Kelly Winterton bred many new varieties from seeds of his original strain and a few other varieties were found but i get the impression that genetic diversity of potato onions in america is still rather low.
Am i wrong?
I was very surprised when I found 30+ accessions of potato onions from different countries in europe in the nordgen genebank and thrilled when I received 25 different accessions.
They all turned out to be potato onions.
There is many different colours, but i didn't get the large bulbed plants i was hoping for.
Conditions were very poor this year though.
I was already going to drop them and forget about them but it seems like a huge waste and pity if people here are interested in potato onion diversity.

Some bulbs available for sharing

project update by
Monday, August 8, 2022 - 05:46

This is a follow-up to my previous post (27 July 2022). I grew out some of the multiplier onion seeds that I got from EFN this spring. They did well, I ended up getting around 50 bulbs. I plan to re-plant about half of these. The other half I am happy to share with members of the group here. If interested, please email me separately to work out the details:

There appears to be three main morphologies (tan skin, reddish skin and white skin) see photos below. Some of them formed multiple bulbs the first year, many just formed single bulbs. A few of the single bulbs were quite large (>2 inches in diameter).

2022 Update: Second year bulbs

project update by
Thursday, July 28, 2022 - 02:28

This is a follow up post to my October 2021 post. Of the 8 bulbs that I planted in the fall of 2021, 4 plants survived all the way to summer 2022, producing 8 bulbs total. All of the plants produced flower stalks in the late spring, which I removed when they were young, to get better bulb growth.
One plant produced 5 individual bulbs, centered around a central flower stalk. Three plants produced single bulbs next to a flower stalk. See photos. I plan to plant all of these this fall, keeping track of which ones were from the plant that produced the five bulbs.

Also, this spring I was able to get some new seed from Experimental Farm Network, which I grew out. These did rather well this year. I will post another update about these later this summer, when they are done drying down. I anticipate having enough bulbs that I should be able to share some with interested members. I'll post more details about this a little later this summer. Stay tuned.

they are still here

project update by
Monday, July 25, 2022 - 07:52

ok. I have 5 remaining plants. 2 of them have been transplanted to a different location. The 3 remain in the semi-protected hoop house and have flower stalks. That's all. I did collect some seeds last year.

Onions going to flower in 3rd year

project update by
Thursday, May 12, 2022 - 06:07

All of my surviving 3rd year potato onions are flowering. This is the same thing that happened with the onions in their second year (100% of survivors flowered). I was under the impression that by the 3rd year some of them would not be flowering and would simply divide. The flower stalk prevents the onion from bulbing up much like they did in the first year. Can someone with more experience comment on how many years of replanting until the flowering starts to subside? Is there any difference in flowering and dividing behavior when overwintering in the ground vs overwintering in dry storage? Thank you!

All the Seed I have has been spoken for

project update by
Thursday, February 10, 2022 - 03:26

Hi everybody,
All the potato onion true seed that I have has been spoken for. As soon as I receive a SASE from those who have contacted me, it will be in the mail.
Happy gardening

Communicating about true seed for potato onions

project update by
Monday, January 10, 2022 - 10:17

Hi all
I posted earlier that I do have some true seeds for potato onions. I have gotten a couple of emails saying someone has commented about getting seed, but when I come to this site I don't see anything as far as comments. I would like to connect with those who would like seed. I want it get it to folks who will grow it out. Would want to to send me a stamped, self addressed envelope and I will send it back with seeds. Please email me at Wish there were a way to do a private message on this site.

Potato Onion Seed

project update by
Thursday, November 11, 2021 - 08:23

Hi all
I'm just beginning to see results on a germination test for the potato onion seed I harvested this summer. So far 5 days in it is better than 50%. How does distributing seed though this group work? I would love to give seed to those who would grow it out. My initial seed came from Kelly Winterton in December 2017. I got both his Green Mountain and SSE seeds and am not sure which these are descendants of. I have about 1/4 cup of seed which seems to amount to about an ounce or something in the neighborhood of 7000 seeds or enough for about about 50 packages of over 140 seeds each. Definitely enough to get someone started on the "find a locally adapted variety" hunt. How do we proceed from here?

2021 results / 2022 Goals

project update by
Tuesday, October 5, 2021 - 04:17

My goal this year (2nd year growing potato onions), was to produce seeds from those that were started in 2020. In 2020, I spring planted about 24-25 surviving seedlings that were harvested in August. Then fall planted in October, 2020 at the same time I plant my garlic. About 1/3 of them did not emerge in 2021.

About 6 of them flowered and after cutting the flower stalks/stems and leaving in a glass of water for a few weeks, was able to dry the flower heads and collect seeds.

Yields of the 2020 plants were low, but it gives me seeds to start with in 2022.
I also planted about 15 more seedlings in 2021 and will use these and the 2020 bulbs in 2022 to try to produce better yields. I am thinking of planting about half in the fall and half in the spring to compare how they do.

Segregation from both batches has been ~50% with varying degrees of red or pink, and ~45% yellows. There was 1 white bulb (~2%)

My original seeds were from the Cultivariable Participatory Breeding Project (OSSI pledged), so they are not directly from EFN, but I believe EFN was probably a contributing source.

I am in Rhode Island (USA), on the edge of zone 6b/7a.

Some Success in 2021

project update by
Tuesday, October 5, 2021 - 02:07

I bought some seeds from EFN back in January 2021:
I am in zone 7 (Maryland). I had pretty poor germination, only about 10 plants sprouted.
-Planted them indoors on 05 February
-Transplanted outside on 09 March
-Harvested 8 plants on 16 July
(Note: They did survive quite a bit of onion maggot pressure in the late spring).
There is definitely some variation in size, color and shape of the resulting bulbs. See photo. They are not huge, the largest is about 1.5 inches in diameter.
I plan to plant these in the ground later this month to overwinter them and see what happens in the spring. If I do get more bulbs or seeds, I'd be happy to share. I will keep you posted.

Need Advice on when to collect Potato Onion Seed

project update by
Friday, July 9, 2021 - 06:37

Hi all,
I have 8 large potato onion seed heads and am trying to figure out how long I need to leave them, some of them are trying to fall over. Currently the seeds inside the seed capsules are black but very juicy. Can I bring them in now or do I need to leave them outside until the seed is dry and the capsules begin to split. I live in a humid, high rain area in East TN. I did bring in several other seed heads that had fallen over, but the seed in them does not appear to be maturing. If they dry down I will do germination tests to see if they are live.

Attaching a photo. The lavender seed heads in the background are elephant garlic.


project update by
Sunday, May 30, 2021 - 05:46

My shallots seems to all be blowing to flower. Sante, dutch yellow potato, dutch red, and french red. They were planted on Halloween. NY zone 6bish
Very dry spring, turned very hot. Last day or two is freakishly cold and very rainy. Hope they don't rot. I am disappointed they are mostly going to flower. I was hoping only a couple would and I would have most for storage. Will probably caramelize and freeze after harvest. Will be interesting to see a hybrid of yellow potato and a red shallot. The first shallots I grew were french red last year. I harvested shallots smaller than what I planted, unfortunately. Hope this year will be better.

The assorted bloomers are in the bed on the left. Grey Griselle on the right. They certainly look different in color and growth pattern. GG never stood up straight like the other shallots. They are also lighter green, thinner leafed, and longer leafed. They also constantly divide as they grow. Regular shallots I see, if they come up with 6 plants, you harvest 6 plants. GG if they come up with 6 plants, every few weeks they keep multiplying. One GG has 41 plants!!