Potato onions- the easy-to-grow “perennial” crop

Tristan Vitali wrote:
... The big thing to watch for with them is the neck thickness - use any with thick necks as they'll be least likely to make it to spring.

That's interesting. I was wondering what other factors contribute to storage. Thanks for sharing.

I was also wondering  about long day versus short day.  Do you think that how far north you are is contributing to the small size?  Or your shorter seasons?

I found a good writeup on potato onions on Cultivariable that I don't know if I posted above:

Cultivariable - Potato Onions

Lots of interesting info in there.  Supposedly there are more long day than short day potato onions.  I suspected this...it's a part of my reason for getting them going from seed in the past couple years.  I'm down in the short-day latitudes.

So Tom, do you see any storage differences among your wildcrosses?

Yes.  

The original yellow potato onion (YPO) stock keeps better than the YPO stock being grown out from pure strain true seed.  I did not expect this and I think this will reverse over time.  The original YPO stock I received from a neighbor who had been growing them out and replanting them faithfully every year since the 1950s.  I have been growing the original stock every year since they were gifted to me.  Perhaps the original strain still being reproduced vegetatively is now locally adapted and this has something to do with this circumstance.  The original YPO strain reproduced vegetatively regularly keeps for up to 1 1/2 years though at a high loss rate towards the end.  I consider such a long storage rate a trait worthy of selecting for because it gets the remaining stock to spring planting time of the second growing season since harvest, which acts as an insurance policy against a failed season/crop.  But this kind of timeframe is expecting a lot.  At this point many of the bulbs of the original YPO grown out from pure strain true seed keep as long but there is a much higher loss rate.

My shallot strains regularly keep well in storage through my long winter months until spring planting time, then decline rapidly by around the one year mark since harvest.  That is all I expect of them is to make it to springtime and maybe the next fall for fall planting.  (In fall I plant a lot of old stock as well as new stock.)

My crossed up PO stock is highly variable and keeping qualities are generally not as good as the original YPO strain.  This is a young project and time will tell but I think things will work out to my satisfaction.

Failure in storage/poor keeping qualities to me is my number one means of selecting against undesirable/feeble strains.  This has meant that shallot strains are consistently maintaining a lower percentage of the crop being planted every spring and fall.  I am fine with this.  

Poor keeping qualities and early sprouting in storage was the primary reason I abandoned all my Kelly Winterton PO stock...

It should be noted that my crop is harvested second half of July/early August and spring planting time for me is second half of April.  That is a very long time to be storing anything.  (I also fall plant.)

I feel how I harvest is a major factor on keeping quality.  I try to let bulbs dry down completely in the ground and then harvest cured bulbs just before the next rain.  Plants finish off at a variable rate so this harvest process is repeated over a couple of weeks but always before the next rain event.  POs have a short dormancy period and mature bulbs ready for harvest for storage getting wet is just not a good thing.

I left them in the greenhouse with temps reaching about 110F in the day and down in the 50s at night.  After about a month, I sorted them out - first removing any that rotted or softened dramatically. Then I sorted them by size. So what was left were potato onions that could really last in bad conditions.

I like the way you think, yours is radical selection.  I cure my crop in the ground then harvest, clean, and trim.  I store my stock at a constant 50 degrees in total darkness.  I inspect stored stock monthly and cull out any sprouting or rotting bulbs.  Rot begets more rot, causing faster decline of remaining inventory.

...they never used a whole onion and so half would often go to waste.  So a small onion was a plus!  I would never have guessed that benefit because when I cook even for only myself, I use at LEAST one onion.  Lots of onions in my diet.  So the small size is a tad annoying to me, but I still like potato onions for how easily they multiply and grow, and how well they store.

I am the same way, much preferring the smaller onions as I can use what I need and have no leftovers in the fridge.  To me prepping the smaller size bulbs is no different than prepping garlic cloves.

Tom Knippel wrote:

It should be noted that my crop is harvested second half of July/early August and spring planting time for me is second half of April.  That is a very long time to be storing anything.  (I also fall plant.)

What zone are you in, Tom?  Where I am in the desert, zone 8a, near the US/Mexico border, I can also plant them in the ground in late fall and let them grow all winter.  Also, in Oregon I could fall plant as long as the ground they were planted in wasn't going to flood. The difference here in the desert is that they do need supplemental water in the winter.  Oregon was a little simpler that way.  But I like having living and growing plant roots in garden all times of year, and onions of all types are a great plant for that in my climate.

I really like how you are aiming for long storage times, and flexibility on planting time.  That strikes me as keeping the original versatility of the potato onion.  I think this is why the onion has been a cultivated crop for millennia now - it's incredibly versatile.  It comes with a protective storage wrapper (can't say that for potatoes or carrots...),  it can be carried over long distances then plopped in the ground in a totally new region (wet or dry, hot or cold) and still grow and produce food even if the timing/season isn't optimal.  That's a fantastic plant!

It's fascinating that even with the day/night length sensitivity it's still become a primary crop.  I suspect the day/night length characteristic might also have benefits we haven't figured out yet.  I have often found in my life that hurdles have advantages that we haven't yet perceived.

When I share with new people about potato onions, I try to explain how they came to be through that vision of nomadic peoples, or trade routes, or just the settlers across the Americas. This is the sort of plant you could tuck in a leather satchel, carry long distances, and start your garden with...fast.  

Those genetics are not just an interesting part of history; they are something we may all benefit from in the future.  Food security in the face of shortages or distribution issues is one hot topic today, but even if that doesn't happen on a major scale - what if commercial onions develop some very successful pest or disease that wipes out a lot of the crop or varieties, or even damages the storing ability?  Long storing potato onions could hold the key to salvaging the monocultured genetics that dominate the food system right now.  

I don't think I've pointed this out well enough in this thread.  Today it occurred to me that maybe it's not an obvious thing to everyone reading this thread, rather than those of us participating in the development of these new varieties.  Sometimes it seems to "obvious" to me why I'm doing something and I forget how inexplicable it looks to others!  Until I get those quizzical looks - they help remind me.

Now I'm curious as to what other people's friends and neighbors think of these potato onion experiments and how one communicates the purpose.

Tom Knippel wrote:
I feel how I harvest is a major factor on keeping quality.  I try to let bulbs dry down completely in the ground and then harvest cured bulbs just before the next rain.  Plants finish off at a variable rate so this harvest process is repeated over a couple of weeks but always before the next rain event.  POs have a short dormancy period and mature bulbs ready for harvest for storage getting wet is just not a good thing.

... I cure my crop in the ground then harvest, clean, and trim.  I store my stock at a constant 50 degrees in total darkness.  I inspect stored stock monthly and cull out any sprouting or rotting bulbs.  Rot begets more rot, causing faster decline of remaining inventory.

These are great tips on storage.  

Yes, I was doing radical selection with the greenhouse treatment - part because I didn't want to have to store them and the other factor being that I didn't have enough room to grow out the whole crop.  But I still wanted to have some information about which ones may have stored well.  

And then it occurred to me that if I shared them with others in our local seed/plant share group, I would get free labor.  (To any of my neighbors reading this, please know I'm joking...sort of.)  They will grow them out, we will see which are successful, and most importantly who likes them.  I don't know if they all realize they were enlisted in a worldwide potato onion breeding project.   I think this counts as "infecting minds [and gardens] with permaculture".

Kim Goodwin wrote:

Tristan Vitali wrote:
... The big thing to watch for with them is the neck thickness - use any with thick necks as they'll be least likely to make it to spring.

That's interesting. I was wondering what other factors contribute to storage. Thanks for sharing.

I was also wondering  about long day versus short day.  Do you think that how far north you are is contributing to the small size?  Or your shorter seasons?

I found a good writeup on potato onions on Cultivariable that I don't know if I posted above:

Cultivariable - Potato Onions

Lots of interesting info in there.  Supposedly there are more long day than short day potato onions.  I suspected this...it's a part of my reason for getting them going from seed in the past couple years.  I'm down in the short-day latitudes.

I don't know for sure that the variety I'm growing is a long day, but I do suspect it is. I ordered these from territorial seed, which no longer carries them evidently, so not sure how to check on that. They always attempt to flower and we use those for salads (or just eat them straight in the garden!). Spring planting might keep them from attempting to run to seed, but would cut deeply into their growing season as they often are up and growing before the ground has fully thawed (they emerge about as early as the daffodils and garlic). They are definitely hardy enough for the far north which leads me to think they're a northern variety, at least

I really can't point to anything other than soil - we're working our way up from dense, heavy clay with nearly no organic matter, so the soil conditions are always a huge factor for them here. Freshly turned soil full of nitrogen rich organic matter like clover produces more per cluster, and generally larger with sweeter flavor while beds that haven't been turned in a year or two with little organic matter tend to produce smaller, fewer and much stronger tasting. Sort of obvious on that end. The smaller and stronger onions have always been our best keepers up to this point which I put down to the concentration of sulfur compounds and amount of water content. Could be wrong on that.

We also do nearly no irrigation having a fairly consistent 3 to 4 inch rainfall per month through the growing season. Some years, though, aren't that easy. We've had a few droughty years with less than 1 inch per month for a month or two as well as other years with upwards of 6 inches per month for a month or two. Last year we got both in the same season! Every year is different here in northern new england

Breaking things out a bit, though, and sussing out what I can about their behavior with different conditions, it seems that nitrogen and water seem to be the biggest factors for size, while water and organic matter seem to be the biggest factors for flavor and number per cluster. It's hard to say that all three aren't inextricably linked in my soil, however as organic matter = nitrogen = steadier soil moisture levels. Nitrogen fertilization alone seems to increase size somewhat, but doesn't seem to lead to more per cluster.

And good news for mid winter: the higher nitrogen content of the partially composted chicken manure on last year's beds hasn't affected storage any. I was expecting a lot of soft onions by about now. With still another 4 months to go before the green onion / scallion is ready to take over for them, it's still a question in my mind, but so far we've had comparable to maybe better storage than previous years.

I came across this post while looking up more info on potato onions, after learning of their existence by stumbling across Full Sky Farm while searching for a seller of Egyptian Walking Onions! I actually just ordered some Green Mountain bulbs from them, so they must have just had a dry spell or something, since they're currently selling them!

Cathy James wrote:"FullSkyFarm on Etsy sells bulbs and seeds from three varieties, including Green Mountain."

I have checked their offering periodically over a period of many months without ever seeing Green Mountain bulbs offered, only seeds. I would like to get some Green Mountain bulbs, which will be easy to start and breed true, rather than seeds, which are a pain to start and will be an F2 generation that doesn't breed true.

Have they stopped offering bulbs, or did they just have a year when supply didn't meet demand?

Does anyone know where I could get Green Mountain multiplier *bulbs*?  Or perhaps Dakota Red, or Dakota Gold?  I have been unable to find bulbs for sale for any of the varieties that Kelly Winterton created, despite a lot of looking online.

Welcome to Permies, Kathryn!

I'm glad you found this post.  It was created as an attempt to catalog most of the core sources of information found on the net, as well as sources for seed and bulbs of potato onions.  

Potato onions are only seasonally available, and so it is good that you've found some.  Let us know how they do for you!  

I love this thread, and how I continue to be educated by people writing into this thread with new information.  Glad you found it and thanks for sharing.

That's correct. Potato onions are only seasonally available, as I eventually learned. Plan to order in late summer or fall, and don't expect to find any in spring.

I did get some Green Mountain Multiplier potato onions, but many died the first year. I'm unsure if I will have any at the end of the second season here. They don't seem to do as well here as the common yellow-brown small potato onions.

Cathy James wrote:I did get some Green Mountain Multiplier potato onions, but many died the first year. I'm unsure if I will have any at the end of the second season here. They don't seem to do as well here as the common yellow-brown small potato onions.

Good to know - was thinking about trying these myself at some point. My seed-saving trials from whatever variety / selection of potato onion I have produced no plants at all a couple times already. The hope was to breed for improvement in size and quality, hence looking elsewhere when the saved-seeds proved sterile, but at least what I've got is hardy enough to handle the tundra

Fall 2020 I planted 145 yellow potato onions purchased from SESE, and slowly increased the number I planted during subsequent years. Last fall I planted 430 bulbs and this summer I harvest 2420 bulbs, which means I'm finally sustainable with onions. This fall I'm incorporating Green Mountain potato onions into my garden. Love these onions!

I'm planning on trying to get my hands on some seed this year and give these perennial onions a shot at growing. I already keep egyptian walking onions with good success but I would appreciate some onion-based diversity in my growing spaces.

Amazing harvest. Mitch!

Kim's comment on growing them in Oregon and then high desert suggests they might work in my region with hot dry summers. I want to try them but don't want to waste my money or the plants! Our garden is zone 7b dry steppes, very hot summers with next to no rain, coldish winters with lots of frost but little snow, usually around 15 to 18" of rain from October to April then drought.

Our neighbours have a flourishing garden and produce huge garlic and good onions but they irrigate heavily. I can't, for the next two years I'll only be there for a week a month during the growing season. I want to try to get some perennial crops started and need plants that will survive drought with a monthly deep irrigation but scorching sun and very little water in between. Even eventually when I'm there full time I'd prefer not to have to water too heavily, so I want to select for things that will get by with less water. The region is getting hotter and drier. The alliums in my garden (garlic and shallots that were already there and got through three years of complete neglect) are surviving, just, but the leaves die off early in summer and I only get small crops of tiny bulbs.

I hope you all enjoy this podcast episode as much as I did. This has Joseph Lofthouse, Holly Hansen, and Kelly Winterton discussing potato onions!



For even more information, check out Kelly Winterton's website - https://sites.google.com/site/kellysgarden/potato-onions

A unrelated website to these folks but is full of information on potato onions - https://www.potatoonionguy.com/home

I really enjoyed this thread! Hadn’t heard of potato onions before but the name alone makes me want to know more. I’m going to watch the videos now to see if there’s any hope of growing them here in zone 11. It’s been a while since I’ve grown any food crops but I was making plans earlier today for a trellis for Malabar spinach. The guy helping me still doesn’t believe me when I pointed out the wild purslane and told him I used to gather and eat it regularly.

Timothy Norton wrote:I hope you all enjoy this podcast episode as much as I did. This has Joseph Lofthouse, Holly Hansen, and Kelly Winterton discussing potato onions!

youtube vid link

This was very well worth the listen - thanks Tim  

The only problem is that differences between "potato onions" and "multiplier onions" is still just as clear as mud to me. Was the idea that potato onions actually die out after a second year when planted from seed, so you HAVE TO plant from seed again every two years? Or ... are they multiplier-like and popping an onion in the ground just produces more onions again, year after year? Something about this doesn't seem right to me.

Either way, it seems my strain of multiplier - or are they potato? - onions is sterile...they flower every year reliably for me (approaching 10 years already!) but the seed they produce will not sprout, even when crossed with other onions. Very disappointing on that front as I was hoping to rejuvenate them / reselect for production in my heavy clay and lack of attention

Note: hope "Tim" is ok - writing your full name gives me an error message about the "in my opinion" abbreviation (doh!)

Great question Tristan,

My understanding (which I could be wrong, I'm new to learning about these onions as well) is that potato onions are a variation of multiplier onions. Potato onions have the ability to sometimes produce seed while also producing multiple bulbs.

Example of Multiplier Onions
1. Potato Onions (Yellow, Green Mountain)
2. Shallots

I consider Egyptian Walking Onions to be a top setting onion but I have heard arguments that they are multiplier onions in themselves. I think the term is loose enough that it catches a lot of things under it umbrella but can be used interchangeably with the official names depending on the context of the conversation.

Tim has that right. I have potato onions that have been growing and multiplying for five years. They have produced substantial seed bounties twice, though I think that's an unusually high return -- I just happen to have gotten lucky.

Cut and paste from another post:

The only multiplier I've had great success with is one LSU supposedly came up with in the 1930s. They almost got lost and that would have been a shame because they're almost bulletproof here, whereas other onions can be a little tricky. They will grow in the shade or sun, just scratch a trench in the ground, throw them in, bury them and they'll go. One bulb will give 5 - 8 bulbs at harvest. They'll struggle through the summer but better planted any time from Sept. on and harvested in the spring.
Hoss sometimes or Lazy Dog have them and they pop up on Ebay now and again.

https://lazydogfarm.com/products/louisiana-evergreen-shallots

Best guess would be these are short day. I'm in N. FL, zone 9

I have tried all the walking and potato onions with zero success.

I'm trying elephant garlic as a perennial and it's looking like that's going to work. Planted the corms last winter and have large plants looking good this winter. Elephant garlic is actually a leek, which explains why you get one bulb and  no multiple cloves if you pull it in its first year.

Timothy Norton wrote:Great question Tristan,

My understanding (which I could be wrong, I'm new to learning about these onions as well) is that potato onions are a variation of multiplier onions. Potato onions have the ability to sometimes produce seed while also producing multiple bulbs.

Example of Multiplier Onions
1. Potato Onions (Yellow, Green Mountain)
2. Shallots

I consider Egyptian Walking Onions to be a top setting onion but I have heard arguments that they are multiplier onions in themselves. I think the term is loose enough that it catches a lot of things under it umbrella but can be used interchangeably with the official names depending on the context of the conversation.

Thanks Timothy - that makes good sense. Whatever I've got definitely multiplies well and follows all the logic seen throughout the thread (large bulbs planted yield numerous smaller bulbs / smaller ones planted yields one or two larger), plus they seem to have a fondness for fluffed, nitrogen rich soil (and love a heavy mulch of rotting hay). I've seen upwards of 10 smaller bulbs off a single large multiplier bulb planted in the fall - always so rewarding

Also going to try doing a bleach water dip mentioned in the podcast in the coming years, just to see if I get a difference. We've mostly lost a strain of siberian garlic that was producing massive heads to disease - even in dry soil on dry years, the wrappers are sometimes completely rotted off before the scape coils. Very sad to see!