How to Grow Green Onions (Regrowing & From-Seed Guide)

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 the USA
  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 (Regrowing & From-Seed Gui...
  14. Growing Green onions in another region
  15. Sources
  16. Frequently Asked Questions

Two ways to grow green onions: regrow the white base of a store-bought bunch in a glass of water for a quick extra harvest, or sow seed direct for a full garden crop — timed to your own last frost date rather than a fixed calendar date, since they're pulled young and never reach the bulbing stage that governs a bulb onion's sowing window.

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 54-77°F (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.

The fastest way to a green-onion harvest doesn't start with seed. Illinois Extension: "Save the bulbs (the white part with roots) of your green onions... place in a shallow dish of water... Place in a sunny window and watch as new greens emerge from the top of the bulb." A widely-shared kitchen hack for good reason -- new growth shows within a couple of days on a sunny windowsill. UC Agriculture and Natural Resources adds one real caution for the water method: don't use chlorinated water, and change it every couple of days as it clouds. Expect full-sized regrowth in about a month; flavor and vigor fade after a few cycles, so treat it as a free bonus crop rather than a long-term replacement for sowing.

When to plant in the USA

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.

United States. Spring onions have no single planting window, because they are not timed against bulbing. Bulb onions must be sown early enough to make leaf before long days and heat trigger bulbing — plant too late and they make leaves and never bulb — but spring onions are pulled young, from about 50 days after sowing, and never reach that stage. That frees them for succession sowing: a short row every two to three weeks from as early as the ground can be worked until late summer gives a continuous supply rather than one glut. Sow 1/4-1/2 in deep in rows 8-16 in apart. Unlike bulb onions they can be left at closer spacing and thinned as they are used, with the thinnings eaten.

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

  • 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.

Recommended by the 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 (Regrowing & From-Seed Guide) planting

When to sow and plant Green Onions (Regrowing & From-Seed Guide) depends on your own frost dates. Check the USA 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

  2. US extension source: sow 1/4-1/2 in deep in rows 8-16 in apart, with seeds, sets or transplants 3-4 in apart in the row; green onions harvestable from about 50 days after seeding while bulb onions need 100-120 days; onions bulb under long days and hot weather, and planted too late in spring most will grow leaves and never bulb; green onions can be left at closer spacing and thinned as they are used; leave bulb onions until the tops fall over, then dry 1-2 weeks until skins are papery; store cold at 32-40°F and dry.

These 2 sources are 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

Almost everything on this page resolves to your own frost dates rather than the calendar — the last spring frost moves by roughly two months between zone 3 and zone 10. The USA Garden Planner works from your zone so the timing is already decided before the season starts.

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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 USDA hardiness-zone and frost-date data, with Cooperative 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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