herb
EdibleGreen Onion / Scallion
Allium fistulosum
Toxic to cats and dogs — keep it out of reach (source: ASPCA (Allium / onion family)).
Some direct sun — an east or west window, or a few hours of direct light.
Keep evenly moist — water when the top inch of soil is dry.
Forgiving and beginner-friendly.
Green onions are the classic regrow-from-scraps crop and almost foolproof on a windowsill. Snip what you need and they keep coming back. The onion family is toxic to cats and dogs, so keep them out of reach.
About Green Onion / Scallion
Green onions (Allium fistulosum), or scallions, are the classic regrow-from-scraps crop and close to foolproof on a windowsill. The species comes from East Asia and has been grown there for centuries. They're ideal for a renter with almost no space: a 2-litre pot, medium light, and the leftover root ends from a shop-bought bunch are enough to start.
Stand the white root ends in a glass of water, changing it every couple of days, and the tops regrow within days. Cut about 2 to 3 cm above the white base so the plant keeps going, and move it into soil for stronger, longer-lasting regrowth. A first snip can come in as little as 21 days. After several cut cycles the regrowth thins out, at which point you start again from fresh ends.
What it’s like to grow
Green onions are easy and quick to regrow, a good pick for a beginner or anyone testing whether they can keep a plant alive. The main trouble comes from leaving the bases too long in stale water, which turns them slimy and weak. Paler, thinner regrowth after a few cuts is normal and just means it's time to refresh from new ends. One caution: the onion family is toxic to cats and dogs, so keep the pot well out of their reach.
What to expect
First harvest in about 21–60 days. It’s forgiving, so it’s a good one to learn on. No sunny window? It also does fine under a clip-on grow light.
See what you’ll need to get started ↓♻ Regrow from scraps
Stand the leftover white root ends in a glass of water (or pot them) and the green tops regrow in days.
Companions
Tips
- Regrow from store-bought root ends in water, changing the water every couple of days.
- Snip the green tops about 2–3 cm above the white base so they regrow.
- Move to soil for stronger, longer-lasting regrowth.
Common problems
- Slimy, weakening bases if left too long in stale water.
- Thinning, paler regrowth after several cut cycles (refresh from new ends).
Common questions
Is Green Onion / Scallion toxic to cats and dogs?
Green Onion / Scallion is toxic to cats and dogs if eaten, so keep it out of reach of pets that chew. Source: ASPCA (Allium / onion family).
How much light does Green Onion / Scallion need?
Green Onion / Scallion does best in medium, indirect light: near an east or west window, or a little back from a bright one. Direct midday sun can scorch it.
How often should I water Green Onion / Scallion?
Water Green Onion / Scallion when the top inch of soil feels dry, then let it drain. Aim for evenly moist, not soggy.
What temperature does Green Onion / Scallion need?
Green Onion / Scallion is happiest around 13–24 °C. It tolerates brief dips to about -7 °C, but cold drafts and sudden chills set it back.
How long does Green Onion / Scallion take to grow?
Expect a first harvest about 21–60 days from sowing under good conditions. Snip the green tops repeatedly and they keep regrowing for many cuttings.
Can I grow Green Onion / Scallion without a sunny window?
Yes. Green Onion / Scallion does well under an affordable clip-on grow light, so a bright window isn't essential.
How big does Green Onion / Scallion get?
Slim upright stalks ~0.2–0.3 m tall; grow many close together in a clump.
How do I propagate Green Onion / Scallion?
Sow seeds, or regrow by standing leftover white root ends in water or soil.
What pests affect Green Onion / Scallion?
Watch for thrips, aphids and onion flies. Check new growth and the undersides of leaves often, and treat early with a rinse or insecticidal soap before they spread.
Is Green Onion / Scallion easy to grow?
Yes. Green Onion / Scallion is forgiving and one of the better plants to learn on.
Gear for Green Onion / Scallion
Gear suggestions to get you started — general picks, not paid placements.
Pet-toxicity from the ASPCA. Care details are general guidance, not professional or veterinary advice; only eat plants you can positively identify as the edible plant and part described. Photo: Salicyna, CC BY-SA 4.0, via Wikimedia Commons (CC-BY-SA). Care info last updated 2026-06-02.