Potato Onion Grex

Allium cepa var aggregatum
Also known as bunching onion, multiplier onion, perennial onion, perennial bulbing onion, shallot

$5.00

In stock

Description

Potato onions are a true perennial onion and are the only bulbing onion that we grow on this homestead. As a grex this population of potato onions is diverse and includes shades of white, brown and red onions.

One of the best things about potato onions is that they are versatile and can be grown from seed or by replanting bulbs that were harvested and cured. Potato onions can also be left in the ground to multiply on their own and may eventually have smaller bulbs and numerous stalks that resemble other bunching onions.

First year onions grown from seed can get as big as a large baseball, perhaps even larger in ideal conditions. Onions that are replanted will divide in the following year into 2-8+ onions, in a cluster called a nest.

One of the reasons I love having dividing onions is that I can both eat and replant my favorite onions and best keepers!

While normal biennial onions are often selected not to divide, potato onions are encouraged to divide so that we can have more, albeit smaller sized bulbs. It’s typical to have onions that produce multiple bulbs from golf ball size to baseball size. Fertility, water and spacing will play a role in how large the onions get.

Furthermore, most of the potato onion send their flower stalk from the base of the onion. Once the onion has flowered, and allowed time to grow a bit more, the onion bulb is not compromised by the flower stalk and can still be stored and eaten. Please know that a small percentage of onions grown from these seeds will produce flower stalks through the center of the bulb.

Another thing that is nice about having perennial bulbing onions is that they are very patient. More that once I have planted onions in less than ideal soil that is lacking high fertility and ideal moisture. The onions hung in there year after year, even growing in grass in some cases. I would make sure to weed them once a year at least. Those onions that didn’t get big in their first year eventually sized up in year 2, 3 or 4. And those onions that are not in ideal locations tend not to flower right away either. You can’t do that with a typical biennial onion.

These onions range in spiciness, but are fairly spicy on average, especially when freshly harvested. They have moderate to high store-ability and some onions make it through winter without sprouting while others will start sprouting in late winter.

Our potato onion grex originally came from the variety of potato onions known as Andy’s Green Mountain Multiplier Onion, who’s genetics are derived from Kelly Winterton’s Green Mountain Potato Onion landrace and include some Strausberger Gelbe potato onion genetics. Prior to Kelly Winterton’s work, potato onions had gone by the wayside and any commercially available potato onions were no bigger than shallot size and did not flower or set seed. After a chance flowering event from his potato onions, Kelly saved seeds and continued to save seeds each year while selecting for vigor, size and diversity of traits. Thanks to Kelly Winterton potato onion seeds are more readily available for enthusiastic gardeners that want to grow an old time favorite onion.

I’ve been growing these potato onions since 2019 and adding new genetics each year. I am selecting for the most vigorous, healthiest, largest bulbs in the least ideal conditions. I continue to put the onions through various trials (many unintentional) including less than ideal water, high heat, soil fertility and harvest time. I am able to select for the most versatile onions that fare well under less than ideal conditions. I am also selecting for disease resistance. The onions are getting stronger and stronger each year and should do well in a variety of other conditions. I am also selecting for onions that flower from the side of the bulb, rather than directly through the center of the bulb.

It’s also important to note that this potato onion grex is day length sensitive and suited for northern growers. We are at 42 degrees latitude and have been selecting onions for our climate. But as a grex it is possible and also likely that some percentage of offspring can be day length neutral. So there is possibility gardeners in other regions to select onions that bulb up nicely in their own latitude.

I’ve come to appreciate growing potato onions for my own personal growing style, convenience, flexibility and perenniality. While potato onions grown as perennials typically won’t be as large as standard biennial onions grown from seed or sets, potato onions are far more versatile in the ways they can be grown, and they can be propagated indefinitely. I personally grow my onions both from seed and from bulb each year. Other gardeners might prefer one or the other. With these onions you have a lot of flexibility and you can even grow them in different ways in different parts of your gardens. It’s so fun to have options!

I am really excited about perennial onions—as mentioned above this is the only bulb onion we grow because it is so fun, diverse, flexible, patient and adaptable. We are so excited to share seeds from these beautiful onions with you!

Details

Lifecycle: Perennial
Lifespan: Indefinitely with cultivation
Hardiness zones: 4-8 (USDA)
Habitats: Not known in the wild
Plant size: 1 ft wide x 4 ft tall
Light: Full sun to part shade
Soil: All soil types, fertile soils preferred, well draining
Water: Moist soils
Seeds per packet: 50+ seeds

Seed Starting

Plant potato onion seeds in late winter, or as soon as ground is workable, as you would any other onion. Onions can be direct seeded, but I prefer sowing densely in flats or nursery pots and then transplant in the spring when they are tall and robust. Some people prefer to wait until the onions are pencil thick, which while not necessary is helpful because the onions are more robust and require less initial weeding and coddling. Cover the seeds with 1/8-1/4″ of soil and keep moist until they germinate.

Onions are cold germinators and I typically sow my onion seed in February. If left uncovered, once germinated, repeated freeze thaw events can heave the onions from the soil exposing the roots. If that happens, carefully tuck them back in the soil as often as needed. Starting onions in a protected area or in a greenhouse is not necessary, but can help prevent that freeze/thaw heaving.

Cultivation

These potato onions are day length sensitive and will be ready for harvest around or soon after summer solstice.

Cultivate potato onions as you would other day length sensitive onions. For first year onions 4-6″ spacing minimum. For second year onions 8-12″ spacing is better since most of the onions will divide and send up multiple leaf stalks and flower stalks.

If seed is not desired, pinch flower stalks as soon as they begin to appear, or as soon as you notice them, and repeat as necessary for each new flower stalk. When energy is not going to produce flowers and seeds the onion bulbs will be larger. Alternatively you can pinch some stalks and allow others to flower.

Harvest

First year onions grown from seed can be harvested when the the plant starts to flop over. Second year and older bulbs can be harvested either before the plant flowers or after. After summer solstice the bulb will continue growing and is more likely to further divide and put on a little extra growth, but don’t wait for the tops to die down if you want to use it as a storage onion.

After harvesting, cure onions in warm temperature out of indirect light and somewhere critters won’t disturb them. Onions are considered cured when the leaf stalk has dried through and through. Afterward onions will store best in a cool, dry location, but they also do pretty good at room temperature.

As a diverse grex, some onions will store longer than others. We eat the ones that are sprouting first, but some onions will go through the winter without sprouting.

Propagation

Onions whose bulbs have divided can be split and replanted. For onions that I want seed from I will plant in November. It seems onions that are exposed to winter conditions are more likely to flower the following year. Otherwise onions can be replanted anytime after the ground is workable.

Cloned onions can harbor disease and fungus. Soaking them briefly in a dilute solution of bleach water, while not necessary, can kill fungus like pink root and ensure larger bulbs. Flowering and seed production can also be tempered by disease.

Seed Saving

Harvest seed stalks from the onion when most of the flowers have dried and black seeds are showing. Thresh the seed heads between your hands, by rubbing them over a screen, or by beating them inside a bucket. Screen and winnow seeds if cleaner seed is desired.

Additional information

Weight0.007 lbs
Dimensions4.5 × 3.25 × .05 in

Reviews

  1. Tara V

    I am so excited to grow potato onions. I have plenty of Egyptian walking onions but they do not produce large enough bulbs to eat so I just eat the greens. But with potato onions you can actually eat the bulbs, which is awesome. The seeds had incredible germination, and the plants are growing really well. Excited to harvest my first onions this year!!

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