How to Grow Green Onions (Spring Onions)

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

Grow green onions (spring onions) two ways, no matter your climate: regrow the white base of a store-bought bunch in a glass of water for a quick extra harvest, or sow seed direct 4–6 weeks before your last expected frost — they're pulled young, around 50 days from sowing, so a local frost date matters far more than a specific calendar month.

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.

Regrowing works the same way wherever you garden. 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 sunny window and watch as new greens emerge from the top of the bulb." UC Agriculture and Natural Resources' one caution: avoid chlorinated water, and change it every couple of days as it clouds. Full-sized regrowth takes about a month on a warm, bright windowsill; flavour and vigour fade after a few cycles, so treat it as a free bonus rather than a permanent replacement for sowing.

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

A few widely available bunching types worth seeking out by name:

  • Tokyo Long White -- long, thick white shanks; a Japanese bunching type bred for size.
  • 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.

Source: University of Saskatchewan's home-garden variety list.

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 (Spring Onions) planting

Timing for Green Onions (Spring Onions) follows soil temperature and frost, not the calendar date. The Global vegetable planting calendar explains the method. 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

These source is specific to this region. 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

This page gives you the thresholds; the planner turns them into your own calendar. It works from what you can observe and measure in your garden rather than from dates written for somebody else’s latitude.

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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 international horticultural research and extension sources. 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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