Potato onion is a common name for a type of multiplying onion. They’re also known as hill onions, mother onions, or pregnant onions.
One bulb can produce up to 8 or more onions.
Where to Plant for Best Results
If you want these onions to do their best, plant them in great garden soil that has an abundance of organic matter. For many years I planted them in my flower borders because I didn’t want to give them much room in the garden. They never produced as well in the flower borders, but they love the loamy rich soil of the garden.
Why Grow Them
I’ve grown yellow potato onions for years in order to make sure I have onions on hand after we’ve eaten all our regular onions by late fall. Back in a time when more people depended on their gardens for their food, potato onions were very popular. In some parts of Virginia they were gifted to newlyweds as a start for their new home garden.
The potato onion is not as sweet for eating fresh as regular sweet onions grown in the spring, but they’re still good, and excellent for cooking. One is usually all you need to flavor a dish.
A White One
There’s also a white multiplier, that I’ve not grown, said to produce green onions for fall use.
Once Started You Won’t Have to Buy them Again
Usually, once you get yellow potato onions started you’ll have plenty to plant the following year and in years to come. But this past winter, I lost all of mine to the extreme cold and will start fresh again this year with ordered bulbs.
Order Early in the Season or You’ll Miss Out
By the way, keep in mind these onions can be hard to find especially if you wait too long to order. To make sure they don’t sell out before you get yours, order in the early spring even though they’re not usually shipped until fall.
I’ve got about 24 bulbs to plant. (Cost was about $24, but once you get them started it pays off.)
How I’ve Always Planted
In years past, I’ve never given a lot of thought to my potato onions. I’ve planted them in the fall. Sometimes October. Sometimes as late as December. I pushed the bulb into the soil just deep enough that the tip is buried. Then covered with a light layer of straw and then covered with another 3 inches of straw or leaves once the weather started to get really cold.
Top growth starts in the fall and can be winter-killed, but will resume in the spring.
When to Harvest
Potato onions are usually ready to harvest by late June or early July. By the time you harvest, they won’t have any live roots, as they go dormant in the summer.
Cure them as you would onions. I’ve had them keep 18 months or longer!
Change of Strategy to Hedge My Bets
Since I’m starting over this year, I’m paying more attention. I’m planting six bulbs in October, six in November, six in December and saving the last 6 for early spring planting.
Fall plantings are said to give the best yields, but saving some for spring plantings to test what does best for you. (Update 8/2019 – I planted in the spring this year and my yields were much better!)
Spacing – You Can’t Cheat
One more thing, you can’t cheat with spacing if you want bigger or more onions. (I’ve tried it many times.) The best spacing is 8 to 12 inches.
If you’re serious about wanting food fresh from your garden all year, you’ll want to start growing potato onions.
How To Have Garden Onions April thru January (tells how to cure onions)
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Are potato onions the same as walking onions? Where did you order yours from?
Theresa, Do they taste the same as regular onions?
Potato onions were recently discussed on a gardening forum and I ordered some from eBay. I received the Green Mountain & Yellow Potato Onions. I think the Green Mountain are the white ones you referred to. I’m really anxious for them to do well. I’m glad you gave the info on lots of organic matter & spacing. I have some great homemade compost, plus aged chicken manure. And I really was planning on spacing them closer than you suggested, so I’ll follow your recommendations.
Thanks for the timely info.
Potato onions are NOT the same as walking onions, Susan.
Walking onions produce small 1/4 inch to 1 inch diameter onion bulbs at the very top of the plant. When they fall over the top sets can take root and grow into new plants. That’s why they’re called walking onions. (They’re also known as top-setting onions.) I use to grow them many years ago. I find the return of investment on potato onions is a lot greater than it is from growing the walking onions.
I ordered my potato onions from Southern Exposure Seed Exchange.
Sandra, as you know, there are many varieties of onions. They all taste a bit different. But basically they all taste like onions. So yes, potato onions taste like regular onions.
Jo-Ann, glad you were able to order your onions. I’ll be most anxious to know how they do for you. Please update me in July.
Something to keep in mind: Yes, potato onions like great garden soil. BUT – don’t over do the chicken manure.
Regarding the compost here’s what I would do: If I had enough I would add about 1 to 2 inches on top of the bed. If you don’t want to leave it on top just lightly scratch it into the soil. Then plant and put straw or leaves on top. Keep in mind that leaves are rich in nutrients and will add just about all the organic matter you need to the soil over the winter.
The bottom line is: don’t over do anything.
Thank you for this information. I have some multiplier onions I need to plant.
I actually like walking onions. They produce onion greens most of the time, even very early and very late in the season. Early in the summer, before they set the hard stock with the little bulbs on top, the whole bulb is very tasty (preferably satuéed in butter with lots of scallops). There may not be a lot of bulb left after it sets the little bulbs, but now in October when I pull them up, I’m getting a scallion-sized bulb beside the hard stalk. They’re easy to plant and forget about. I put them around fruit trees to repel pests or in any spare spot in the garden where they won’t be disturbed. I like companion planting, so have some in with my new strawberry plants.
Great input Heather. Appreciate your taking the time to share your experience.
I like your method of putting them here and there. That’s sure what I’d do if I ever grow them again. That way, they’re out of the way, but you’ve always got that backup for onions when you need it.
after loosing my starters to a really cold winter (-40’s), I got my yellow potato onions from “The Maine Potato Lady”. I received the best service and after being told that they were sold out, they contacted me to tell me that they would be able to fill my order! I still grow some top sets and bunchers, but yellow potato’s are my favorite.
I have recently been blessed with an heirloom top setting garlic. it takes two years to produce the typical ‘cloved’ bulb, but the first year round bulbs (1/4-3/4 inch dia) are to good to describe with words.
The greens of my multiplier onions are falling over. They are small bulbs. Do you know what causes this?
Good to hear from you.
Sometimes potato onion stalks “open” and slant outward. I assume that is what you mean.
Regarding bulb size – two things come to mind:
1. If you plant a larger bulb you get larger onions as a rule.
2. The better the soil the larger the onion.
But — I must say I have not been happy with my potato onions for the past two years and wonder if the ones being sold are somehow a downgrade of real potato onions. I’m just not sure.
Keep in touch. I’d like to know “the rest of the story” when you know it Sue.
My husband thinks a deer was laying on it.
🙂 Oh my!
My potato onions look like they are going to flower. Should I pull them now or let them flower? This is my first time growing them.
Tess, in all the years I’ve grown potato onions, I’ve never had them flower (send up a stalk) until last year. I was
not pleased with the results at all. I’ve read information that does not seem to correspond with the poor results I got. Last year I ordered from a different source to see if it would make a difference. (Of course, the main source could be the same for both suppliers.) The same thing is happening again this year just not to the degree of last year. I’m going to leave mine in the ground and see what happens. Wish I had more information on what’s going on.
I’ve been trailing potato onions for a couple of years with most coming from a Utah Gardner named Kelly Winterton. He bred a variety called Green Mountain from the seed his produced one year, his variety had not produced seed in the previous 15 years he had grown it. The bulbs produced from the seed were very large, up to 4+”! His theory was that the production from seed cleanses the variety of virus built up over the years. The GreenMountain variety he developed has produced seeds for him most years that he continues to select from, as mine have. I did not save mine, but may try to this year.
I’ve had email conversations with him concerning day length sensitivity and we concluded that they might be long day onions. I’m in upstate SC, on the northern edge of the short day zone, so they might not size up for me.
I’ve also had discussions on several forums about onions and garlic acclimating to the area they are in, so I guess I’ll keep them a few more years and see if they size up.
Google Kelly’s garden if you want to find out mare about his line of onions. I think he still has some seed available.