Regrow Spring Onions in Water: Free Greens in 7 Days

Yes — You Can Regrow Spring Onions in a Glass of Water in About a Week

Next time you chop spring onions, save the white root ends instead of binning them. Stand them root-side down in a small glass with 2–3cm of water, put the glass on a sunny windowsill, and fresh green shoots will sprout within days. You can snip what you need and let them keep growing — one bunch can supply greens for weeks.

Why do spring onions regrow so easily?

The white base of a spring onion contains the basal plate — the plant’s growth centre. As long as the roots and this plate stay intact and moist, the plant treats your glass like soil and pushes out new green growth. Spring onions are among the easiest kitchen scraps to regrow because they need no soil, no fertiliser and almost no effort.

How to regrow spring onions in water: step by step

Cut the onions about 4–5cm above the root end — keep the white base and roots intact.
Stand them root-down in a small glass or jar so they support each other upright.
Add 2–3cm of water — just enough to cover the roots, not the whole white base.
Place on a sunny windowsill where they get a few hours of light daily.
Change the water every day (or at least every other day) to keep it fresh and prevent sliminess.
Harvest in 7–10 days: snip the green tops with scissors, leaving 3–4cm so they regrow again.

Tips for endless spring onions

After 3–4 harvests the growth slows — plant the bases in a pot of soil then, and they’ll keep producing for months.
If the water goes cloudy or the bases feel slimy, rinse them and change the water immediately.
A wider, shallow container works better than a tall narrow glass for stability.
Snip from the outside shoots first and let the centre keep growing for the best yield.

What other kitchen scraps regrow in water?

Garlic cloves sprout tasty green garlic shoots in water, the base of a celery bunch regrows leaves, and leek roots behave just like spring onions. Lettuce and bok choy bases will also push out a small second flush of leaves — worth trying before they hit the compost.

Do regrown spring onions taste the same?

Yes — the first couple of regrowths taste just like shop-bought spring onions. After several cuttings the flavour can get slightly milder, which is the signal to move them into soil for a proper recharge.

Common mistakes that stop spring onions regrowing

Cutting the root end too short: if you trim off the basal plate or all the roots, there’s nothing left to regrow from. Keep at least 4–5cm of white base with roots attached.
Drowning the whole base: submerging the white stem causes rot. Water should only touch the roots — 2–3cm is plenty.
Stale water: old water turns slimy and starves the roots of oxygen. Fresh water daily is the single biggest factor in success.
Not enough light: a dark corner produces pale, floppy shoots. A bright windowsill with a few hours of sun gives sturdy, flavourful growth.
Harvesting too early: snipping shoots under 10cm stresses the plant. Wait until they’re properly tall, then cut, leaving a few centimetres to regrow.

Do I really have to change the water every day?

Daily is best, but every other day works if you keep the glass somewhere cool. The danger is bacterial slime, which you can spot as cloudy water or a slippery feel on the bases. A quick rinse of the roots under the tap when you change the water buys extra time. If you know you’ll forget, a slightly larger jar of water stays fresher longer than a thimbleful.

What if my spring onions go slimy or smelly?

Sliminess means bacteria have taken hold, usually from stale water or a base that was already damaged. Rinse the bases thoroughly, scrub off any mushy outer layers, and start with fresh water — most plants recover. If the base itself has turned brown and soft, it’s rotting and won’t recover; compost it and start a new batch with fresher root ends.

When should I move them into soil?

After about three or four water harvests, growth slows noticeably and the flavour mellows — the plant has used up its stored energy. That’s the moment to pot the bases into compost with the green shoots above the surface. In soil with regular watering, they’ll keep producing for months and grow noticeably thicker stems than water alone can support.

Regrow Spring Onions in a Glass of Water — Free Greens in 7 Days