A couple of years ago I began growing multiplier onions for the first time. I had hopes of finding perennial onions that did well in my garden and in our climate. I’ve been growing garlic for quite a few years, and I like how you can save your own planting stock and replant it year after year. With multiplier onions, you plant a single bulb and as they grow they split (or multiply) into a clump of bulbs. So far I’ve planted two different kinds of onions, I’Itoi and Yellow Potato Onion. Both of them are heirloom varieties with a rich history, and both are enjoying somewhat of a revival in the 21st century. They did quite well for me here in the garden, and have proven to be very useful in the kitchen too. I will be planting them outside around the end of October, though I already have some of the I’itoi growing in containers.
planting stock for I’itoi onions
Michelle (From Seed To Table) did a Variety Spotlight in 2016 on the I’itoi, which helped to inspire me to try growing them. I got my planting stock in the form of sets from Native Seeds/SEARCH. They are listed in the Slow Food USA’s Ark of Taste, and the listing there gives a bit of the history and mystery surrounding this tasty heirloom. Michelle gives quite a bit of the history in her post as well, and talks about her experiences growing them.
I’itoi multiplier onions
The I’itoi onions don’t get real big for me, but I find they are most useful as a green onion or scallion. I’ve grown them in ground and in containers, and they do well either way.The clumps do seem to get bigger when planted in the ground, but the container plantings usually give me scallions a bit earlier than the ones in ground. The bulbs resemble small shallots, and can be used like you would shallots or onions.
I’itoi onions planted in a container
There isn’t a whole lot of information available on growing these onions, and at first I wasn’t sure if they would be hardy in our area or not. But they have survived our winters unscathed so far, and last year the temperature got down to -6°F one night. They tend to go dormant here in summer for a bit and dry out, and that is when I usually lift and divide them. If left in place they will start to sprout fairly quickly, and you can see in the below photo many in the clump are doing just that.When planting in containers I set them fairly close, usually 2 to 3 inches apart. When planting in ground I space them about 6 inches apart.
clump of I’itoi multiplier onions
Potato onion is a common name for a type of multiplier onion that is similar to shallots and has good keeping qualities. The Yellow Potato Onion comes from a strain that dates back before 1790, when multiplier onions were widely planted in home gardens. It makes bulbs that can get up to 4 inches in diameter, though mine make bulbs mostly in the 1 to 2 inch range. I got these onion sets from Southern Exposure Seed Exchange, and their Garlic and Perennial Onion Growing Guide has information about planting and harvesting the potato onions.
Yellow Potato Onion
The Yellow Potato Onion is widely adapted for growing in most of the U.S., and is tolerant of drought conditions too. Fall planted potato onions usually get bigger than those planted in spring. The green tops are also edible, though for me the real attraction is the bulbs. Their size is just right for seasoning a lot of dishes, and though hot when raw the flavor mellows with cooking.
clump of Yellow Potato Onions
The Yellow Potato Onions have also survived our winters when planted out in the open ground in late fall. I mulch with a layer of straw to protect the bulbs and to help keep down weeds. You can see them emerging in spring in the below photo, in front of the taller garlic plants. I’ve been spacing them like I do my garlic, in a grid 6 by 8 inches apart. I plant them deep enough so there’s about a half inch to an inch of soil over the top of the bulb.
potato onions in early spring
I hope you have enjoyed this update about growing multiplier onions here in our garden. They have been an easy to grow addition to the garden lineup the last few years. I’ll be back soon with more from Happy Acres!
Excellent article, great links to useful sites, very informative, thank you.
Are these a bit like shallots?
They are botanically, according to the scientists.
Lucky you! I was quite excited about growing multiplier onions – and they did so well here too, even with our harsh winters. But this year, I decided to remove them as I think they were contributing to our leek moth issue, which seemed to get progressively worse each year. Even garlic, which in the past was only marginally affected, will now have to be covered.
Great post Dave! I love I’itoi onions and I hope I’m going to love potato onions too because I just ordered up a bunch from Southern Exposure. I think they will be nice to have around since I quit growing regular bulbing onions because of disease problems. I’itoi onions seem to be more resistant to downy mildew than regular onions and I hope the potato onions are too.
I was wondering if they are anything like Welsh Onions, Dave?
My sister in law gave me some of them. These grow seed pods on the green tubes and that is what you plant. When you use the tops for green onions how should you harvest them. It seems like cutting them and leaving that hollow stem you are using would be asking for bugs or disease. How should this be done safely?
It sounds like you are talking about the Egyptian Walking Onions, which form the small bulbils on the stalks. That is not what I am growing. I do believe you can eat the green tops safely for the kind you are talking about. Here’s more info:
https://wimastergardener.org/article/egyptian-walking-onions/