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Allium cepa

Over the Fields and Through the Woods…

By Beet 2022 09 September

…to grandmother’s winter garden we go. Grandmother sure knew what she was doing when she sowed onion seed in autumn!

Allium cepa, specifically in this case, overwintering onion varieties, are something we northwestern gardeners should consider sowing in our autumn garden plots.       

Why plant onions for overwintering? If you’re looking for more succulent, sweet, and milder onions for your seasonal menus, then these are for you.

Also, given our fickle springs, onions sown at that time often do poorly. It’s very frustrating to find all your diligent efforts result in little to harvest. Slow to germinate, onions that are sensitive to cold temperatures can leave you with very pungent golf balls instead of succulent onion bulbs.

Despite a few challenges, overwintering onions offer not only earlier harvestable bulbs, but also different varieties. Both bulbing and bunching onions can be overwintered. If desired, you can still supplement them with spring sown onions to extend the season.

Overwintering onions also withstand freezing weather. Since they’re in the ground much longer than their spring counterparts, they develop much stronger root systems. Most of their growth also takes place in early spring when soil moisture is most ideal.

These onions also mature and dry in early summer, between June and July, when days are longest for good curing. Hence, you get more superior bulbs that will bring you joy for your efforts as well as the tastiest bulbs.

Sowing overwintering onions in September is best, as the hottest days should have somewhat lessened. For August sowing, you need to select more bolt-resistant varieties to avoid this undesirable occurrence.

Overwintering onions may result in superior harvests and their seed is more vigorous than other types of onions.

To help with sprouting, always purchase quality seed (order from reputable seed companies) and sow only current year seed.

After sowing about ¼” deep, cover seed with fine compost or seedling start mix.  Both hold water and help with germination.

You’ll also want to thin appropriately according to the varieties you’ve sown as overcrowding can result in poor plants. Ideally, you want your plants about ¼ inch in diameter as winter begins.

Although you can sow directly in open garden plots, raised beds are preferable. They not only have superior drainage, (onion seedlings are very susceptible to rotting in heavy-wet conditions) but more friable soil. The use of hoop houses also helps manage moisture during the winter.

Raised beds also hold moisture more evenly–a must for successful overwintering. They help prevent pink root problems and promote general root health by minimizing nitrogen loss. Ultimately, this all means more vigorous bulbs for you to savor earlier.

Onions will start regrowing in late January-February. Once growth starts, side dress them with blood meal, then repeat again in mid-April. Use a complete balanced fertilizer in mid-May.

Once tops start to turn golden (except for bunching onions that should be harvested while still green earlier in spring), stop watering about two weeks before pulling the bulbs.

In no time, you’ll be grateful that grandma had such a great idea. You, too, can enjoy those lovely sweet and succulent overwintering onions.

Seed Sources:

Leeks may also be included for overwintering.

Territorial Seed

They have Red Spring, Hi-Keeper, Walla Walla and White Lisbon bunching onions.


Johnny’s Selected Seeds

They have T-448, Bridger, Desert Sunrise, and Walla Walla along with Bandit organic leeks.



Caramelized Spring Onions and Peppers

1 ½ pounds spring onions (bunching, regular onions or a mix of both) red and/or yellow, washed, roots and skin removed then sliced in 2” pieces for bunching and thin crosswise slices for regular onions

2 large sweet red peppers, washed, stemmed, seeded, and thinly sliced lengthwise

1 teaspoon fresh rosemary minced

1 ½ tablespoons olive oil

¼ cup each sweet sherry and organic apple juice

2 tablespoons balsamic vinegar

2 tablespoons honey or agave nectar

1/8 teaspoon sea salt

Heat oil in heavy-lidded sauté pan until it’s hot but not smoking. Toss in onions, peppers and rosemary.  Cook on medium heat until limp, about 5-8 minutes.  Remove from heat and gradually add sherry, apple juice, balsamic vinegar, honey and sea salt. Stir to mix, then return to medium heat, stirring until it bubbles. Cover with lid and continue cooking on medium low about 15-20 minutes until liquid has concentrated into a glaze and onions are a golden color. Serve hot or cold as relish, on a burger, sandwich or salad, on seafood, poultry or vegan dishes.

Store in fridge.



Oregon State University, dry bulb onions Western OR Dec 2012

Johnny’s Seeds overwintering trials

The Westside Gardener by Travis Saling