How to Grow Green Onions (Scallions and Spring Onions)

Green Onions at a Glance

Sources: Harvest to Table, Illinois Extension, Dixondale Farms.

Scallion vs. Green Onion vs. Spring Onion: What’s the Real Difference?

These three names get used almost interchangeably, and sources don’t fully agree on where to draw the line. University of Kentucky Extension describes true scallions as lacking bulb formation entirely, with spring onions having a more developed bulb, and notes the terms are often mixed up in casual use. Illinois Extension draws it similarly: true scallions have no bulb, while green or spring onions have a small 1 to 2 inch bulb. Harvest to Table adds that in the UK and Australia, “green onion” and “spring onion” usually mean exactly the same thing. For a home grower, the practical rule cuts through all of it: the longer you leave the plant in the ground, the bigger the base gets — pull early for a scallion-style straight stem, or let it sit longer for a more developed bulb.

How to Grow Green Onions From Seed or Sets

1. Sow seed or plant sets directly where they’ll grow, 2 to 3 inches apart, in full sun.
2. Keep soil evenly moist. Shallow roots mean green onions dry out faster than bulb-forming plants left longer in the ground.
3. Sow in batches every 2 to 3 weeks for a steady, staggered supply instead of one big harvest.
4. Harvest at about 6 inches tall, or whenever the thickness suits you — there’s no single correct size.

Growing Green Onions From an Existing Bulb-Onion Bed

If you’re already growing bulb onions, you don’t need a separate bed for green onions. Illinois Extension’s approach: plant or thin to about 2 to 3 inches apart, then simply pull every other plant once the tops are about 6 inches tall. The remaining plants keep growing undisturbed and go on to form full bulbs at normal spacing.

Growing Green Onions From Scraps or Cuttings (in Soil)

You can regrow green onions in soil from the root end you’d normally throw away. Save the white base with about an inch of root attached, plant it root-down in loose, moist soil with the cut top left exposed, and keep it watered and in full sun. New growth usually appears within one to two weeks, and most bases can be cut and regrown two to three more times before the stored energy runs low and shoots start coming in noticeably thinner. This soil method tends to produce sturdier, longer-lasting regrowth than the water-glass method, since the plant can access real nutrients from the soil rather than just what you add to the water. If you’d rather watch roots develop before committing to soil, see our dedicated guide to growing green onions in water.

Growing Green Onions Indoors

A bright windowsill can keep green onions going for kitchen use, but Dixondale Farms advises against growing bulb-forming onions indoors without a grow light — a windowsill alone gives you greens, not properly sized bulbs, because the light intensity simply isn’t enough. If you’re only after a steady supply of green tops for cooking, a sunny window is usually enough; if you want anything resembling a real bulb, you’ll need supplemental grow lights and should expect container-growing results rather than true indoor growing.

Frequently Asked Questions

Final Thoughts

Green onions are the fastest reward in the whole onion family: sow or plant every few weeks, harvest in about two months, and don’t worry too much about whether you call it a scallion or a spring onion. For a completely different, zero-soil way to regrow them from kitchen scraps, see growing green onions in water, or head back to the main growing guide for bulb onions.

How This Guide Was Checked

Written by Ada Jones. Naming distinctions are checked against University of Kentucky Extension, Illinois Extension and Harvest to Table; indoor-growing guidance against Dixondale Farms. Spot a mistake? Contact us and we’ll correct it.