How to Grow Green Onions in Canada

On this page
  1. Green onions (Allium fistulosum)
  2. Quick Facts
  3. At a Glance
  4. Regrowing From Kitchen Scraps
  5. When to plant in Canada
  6. Growth Stages
  7. Soil & Growing Conditions
  8. Harvest & Storage
  9. Bunching Onion Varieties
  10. Diseases
  11. Pests
  12. Companion Planting
  13. Plan your Green Onions planting
  14. Growing Green onions in another region
  15. Sources
  16. Frequently Asked Questions

Two ways to grow green onions in Canada: regrow the white base of a store-bought bunch in a glass of water for a quick extra harvest, or sow seed direct by season rather than a fixed date — on a short Canadian growing season this is one of the few crops where the exact frost date barely matters, since they're pulled at around 50 days, well before hard frost.

The short answer

Ready in
60 days
Site
5+ hours of sun, soil pH 6.6–7.4
Biggest risk
Onion downy mildew

Core growing advice on this page is checked against named horticultural sources — see References.

Green onions (Allium fistulosum)

Freshly pulled spring onions with white bases and green tops on a board. Photo: Kolforn, CC BY-SA 4.0, via Wikimedia Commons.

10 sources cited · Verified

Quick Facts

A bunch of freshly harvested green onions with roots, white shanks and green tops — “Beijing scallions” by Fumikas Sagisavas is licensed under CC0. Source: Wikimedia Commons
“Beijing scallions” by Fumikas Sagisavas is licensed under CC0. Source: Wikimedia Commons.
Factor Value
Soil pH 6.6 - 7.4
Sunlight 5-5 hours direct sun
Optimal growing temp 12-25°C
Time to harvest 60-60 days
Drainage RHS: "Choose a sunny planting site" with "free-draining soil", improved with organic matter.
Lifecycle Grown as a fast annual salad crop, pulled young within about two months of sowing; botanically a hardy biennial to short-lived perennial. Hardy types overwinter to crop the following spring, and plants left in the ground form clumps and flower in a later year.
Edible parts whole young plant (leaves and bulb)

At a Glance

A single unopened Allium fistulosum flower bud among green leaves — “Allium fistulosum in Botanical Garden of Besançon002” by Krzysztof Golik is licensed under CC BY-SA 4.0. Source: Wikimedia Commons
“Allium fistulosum in Botanical Garden of Besançon002” by Krzysztof Golik is licensed under CC BY-SA 4.0. Source: Wikimedia Commons.
Allium fistulosum Spring onion Onion downy mildew Allium leaf miner Leek moth Onion fly Stem and bulb nematode DISEASES PESTS

Regrowing From Kitchen Scraps

Spring onions regrowing from cut white bases in a pot — “Scallions regrowing” by Daderot is licensed under CC0. Source: Wikimedia Commons
“Scallions regrowing” by Daderot is licensed under CC0. Source: Wikimedia Commons.

On a short Canadian season, a windowsill regrowth jar earns its keep well beyond the outdoor months. Save the white base with its roots, trim about 2.5cm (1in) above the roots, and stand it in a glass with just enough water to cover the roots -- Illinois Extension: "place in a shallow dish of water... Place in a sunny window and watch as new greens emerge from the top of the bulb." UC Agriculture and Natural Resources' one caution applies here too: don't use chlorinated water, and change it every couple of days. Indoors it isn't limited by frost at either end, so it's a genuine way to keep picking green onions through the winter, not just a between-sowings stopgap -- though flavour and vigour fade after a few regrowth cycles.

When to plant in Canada

A young Allium fistulosum plant growing in soil, identification label visible — “Allium fistulosum - Copenhagen Botanical Garden - DSC07943” by Daderot is licensed under CC0. Source: Wikimedia Commons
“Allium fistulosum - Copenhagen Botanical Garden - DSC07943” by Daderot is licensed under CC0. Source: Wikimedia Commons.

Canada. No single planting window: spring onions are pulled young, at around 50 days from sowing, so they never reach the bulbing stage that governs when a bulb onion has to be sown. Sow in succession — a short row every two to three weeks from as early as the soil can be worked — rather than all at once. On a short season this is one of the few crops where the frost date barely matters at either end: sow early under cover, and keep sowing until roughly 50 days remain before hard frost. Sow 1-1.5 cm deep in rows 20-40 cm apart, at close spacing, and thin as you use them.

Growth Stages

Allium fistulosum plants in flower, with round white pom-pom flowerheads on tall stems — “Allium fistulosum 2” by Dalgial is licensed under CC BY-SA 3.0. Source: Wikimedia Commons
“Allium fistulosum 2” by Dalgial is licensed under CC BY-SA 3.0. Source: Wikimedia Commons.
Stage BBCH Notes
Sowing & Germination 0 Spring onions are almost always sown direct where they are to grow. SOWING DEPTH & SPACING: make a shallow drill 1cm (half inch) deep, water along the base, and sow the seed thinly, spacing rows about 20cm (8in) apart; thin seedlings to about 2.5cm (1in) apart. TIMING: sow small batches every couple of weeks from March onwards for a continuous supply through spring, summer and autumn; sow hardy varieties in late summer to early autumn to overwinter for a spring crop. An earlier start is possible from a March sowing in modular trays under cover, and they also grow well in a container at least 30cm (1ft) wide.
Leaf & Shank Growth 3 Each seedling grows into a slim plant with hollow green leaves and a slender white shank, barely swelling at the base. Water young plants until they are well established, then only during prolonged dry spells (container plants need watering more often as the compost dries quickly). Weed regularly - hoe between the rows and hand-weed between the closely spaced plants - so the shallow-rooted onions are not crowded.
Harvest 8 Spring onions generally take about two months (roughly eight weeks) to reach harvesting size. Pull them young and mild when about 15cm (6in) tall with the base no more than 1-2.5cm (half to 1in) across - simply lift individual onions with a hand fork whenever you need them, right through spring to autumn. Harvest regularly and successionally rather than all at once, as they do not store and are best eaten fresh.
Bolting, Flowering & Overwintering 6 Spring onions are grown as a quick crop, but plants left in the ground eventually run up a round white flowerhead (bolting), after which the shanks turn tough - so pull them before this. Hardy varieties sown in late summer or early autumn simply sit through the winter and are pulled the following spring, while Allium fistulosum left to grow on forms a perennial clump that flowers each year and can be divided.

Soil & Growing Conditions

Rows of spring onions growing in ridged soil in a field — “Bunching onions growing in a field” by Miyuki Meinaka is licensed under CC BY-SA 4.0. Source: Wikimedia Commons
“Bunching onions growing in a field” by Miyuki Meinaka is licensed under CC BY-SA 4.0. Source: Wikimedia Commons.

Water: RHS: water young plants until established, "then only water during prolonged dry spells"; container plants need more frequent watering. Univ. of Maryland: "Ensure ample moisture, especially after bulbs begin enlarging".

Soil pH range

6.6 7.4

Span reflects genuine variation between the cited authorities, not a single agreed figure.

Harvest & Storage

A crate of bunched red and white salad onions at a market — “Spring onions at a market in Gallicano” by Kritzolina is licensed under CC BY-SA 4.0. Source: Wikimedia Commons
“Spring onions at a market in Gallicano” by Kritzolina is licensed under CC BY-SA 4.0. Source: Wikimedia Commons.

When to pick: RHS: pull salad onions when "about 15cm (6in) tall, with the bulb no more than 1-2.5cm (½-1in) across". Univ. of Maryland independently agrees on the same benchmark: "Harvest green onions when tops are 6 inches tall".

Bunching Onion Varieties

The Government of Saskatchewan's horticulture guidance notes bunching onions are "sown thicker than dry onions and harvested before they form bulbs" -- sow 1.3-1.9cm (½-¾in) deep, in rows 36-46cm (14-18in) apart. On the Prairies, sow as soon as the ground can be worked and keep sowing every two to three weeks until roughly 50 days remain before your area's first fall frost.

  • Evergreen Long White Nebuka -- a cold-hardy standard with long white shanks and reliable overwintering.
  • Tokyo Long White -- long, thick white shanks; a Japanese bunching type bred for size.
  • Parade -- vigorous and uniform with dark green tops; a common commercial bunching variety.
  • Red Spark -- red-tinged shanks for a milder, sweeter bite and extra colour in the kitchen.
  • Kincho -- fast-maturing, slim, non-bulbing shanks suited to close, successive sowing.

Sowing facts: Government of Saskatchewan. Varieties: University of Saskatchewan's home-garden variety list. All grow well in containers as well as in the ground.

Diseases

Onion downy mildew
moderate

Peronospora destructor

RHS names "salad onions" (spring onions) among affected hosts.

Pests

Allium leaf miner
high

Phytomyza gymnostoma

RHS: affects "Leeks, onion, chives, shallot and garlic". [Allium genus-wide RHS pest pages explicitly name multiple Allium crops including chives/shallot; reused for other Allium species in the graph.]

Leek moth
moderate

Acrolepiopsis assectella

RHS: affects "Leek, onion, shallot, garlic". [Allium genus-wide RHS pest pages explicitly name multiple Allium crops including chives/shallot; reused for other Allium species in the graph.]

Onion fly
moderate

Delia antiqua

RHS onion fly page: affects "Onion, shallots, and leeks". [Allium genus-wide RHS pest pages explicitly name multiple Allium crops including chives/shallot; reused for other Allium species in the graph.]

Stem and bulb nematode
high_where_present

Ditylenchus dipsaci

RHS names onions among affected vegetables; Allium family members "swell and distort (onion blout)". [Allium genus-wide RHS pest pages explicitly name multiple Allium crops including chives/shallot; reused for other…

Companion Planting

avoid shared disease

Allium sativum

Both crops are documented hosts of Onion downy mildew. These pathogens persist in soil for many years -- RHS gives up to 20 years for club root resting spores, at least 15 years for allium white rot sclerotia, and advises a five-year gap before replanting onions or shallots after downy mildew --…

avoid shared disease

Allium cepa

Both crops are documented hosts of Onion downy mildew. These pathogens persist in soil for many years -- RHS gives up to 20 years for club root resting spores, at least 15 years for allium white rot sclerotia, and advises a five-year gap before replanting onions or shallots after downy mildew --…

avoid shared disease

Allium cepa Aggregatum Group

Both crops are documented hosts of Onion downy mildew. These pathogens persist in soil for many years -- RHS gives up to 20 years for club root resting spores, at least 15 years for allium white rot sclerotia, and advises a five-year gap before replanting onions or shallots after downy mildew --…

Plan your Green Onions planting

When to sow and plant Green Onions depends on your own frost dates. Check the Canada vegetable planting calendar. To work out where it fits in your beds, sketch your plot in the free Garden Layout Planner.

Growing Green onions in another region

Sowing dates, frost timing and local advice differ by country. Use the guide for where you garden.

Sources

The full list of 10 sources behind this guide (FAO EcoCrop, Royal Horticultural Society, University of Maryland Extension and others) is in the references of our UK guide to spring onions; they describe the plant itself, which is the same wherever it grows.

Frequently Asked Questions

How long do spring onions take to grow?

Typically 60 days, depending on cultivar and growing conditions.

What soil pH do spring onions need?

A pH of about 6.6–7.4. That span reflects genuine variation between the authorities we cite rather than a single agreed figure — the References section lists each source's exact range.

What problems affect spring onions?

Our data links 1 disease and 4 pests to this crop. See the sections above for each one and how to manage it.

Plan next season before the problems start

Short-season growing is arithmetic before it is technique: days to maturity against frost-free days decides what will finish at all. The Canada Garden Planner does that subtraction for your region before you sow.

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SoilCommander Editorial Team — under the direction of Nitin Sharma, Co-Founder

Every growing guide is checked against RHS, USDA Cooperative Extension, and other named horticultural authorities before publishing.

How this guide is put together

The growing data on this page — sowing windows, pests, diseases, soil and site requirements — comes from named horticultural sources, listed in References below, checked against Canadian hardiness-zone and frost-date data, with provincial agriculture and university extension sources cited directly where one exists for a crop. An automated pipeline assembles that verified data into the page you're reading: it selects which facts to lead with and builds the surrounding prose and layout. It does not invent a date, a source or a number — where a verified value for a field isn't available, the page leaves it out rather than guessing. A person reviews and publishes each page; nothing goes live unverified.

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Last verified 2026-09-02

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