why spring onions sold in UK withers very quickly upon regrowing in water

 

The spring onions (also called salad onions or scallions in the UK) you buy in supermarkets are not meant to live long-term — they’re essentially “cut-and-come-again” crops that have been forced to grow very quickly in perfect commercial conditions. When you try to regrow them at home in a jar of water, the leaves often collapse and wither quite dramatically (exactly like in your photo). Here’s why this happens in the UK (and elsewhere):

1. They’ve already used up most of their energy

Supermarket spring onions are harvested when the bulb is still tiny. Almost all the stored energy is in the small white base, and the green leaves are very long and thin. Once cut from the field, that tiny bulb has to support those huge leaves withering leaves with no photosynthesis happening (because they were often stored in the dark). By the time you get them home, the bulb is already running on fumes.

2. UK supermarket varieties are chosen for shelf-life, not re-growability

The varieties sold loose or in bunches (especially the cheap ones from Tesco, Asda, Tesco, Lidl, etc.) are usually fast-growing hybrids that put out long white stems quickly under artificial light and high nitrogen. They are not the traditional hardy bunching onion varieties (like ‘Ishikura’, ‘Evergreen White’, or proper Welsh onions) that regrow reliably for years. Those hardy types are almost never sold as “spring onions” in UK supermarkets.

3. Cold shock + sudden light change

They’re kept refrigerated in the shop, then suddenly put on a warm, bright windowsill. The shock makes the leaves flop and die back even faster.

4. Water-only regrowing in water rarely works long-term with these

The classic “put spring onion roots in water” trick works OK with the bottom 3–4 cm if you immediately trim off most of the green leaves, but UK ones usually have such tiny bulbs and such long tops that the plant can’t sustain maybe one small regrowth before it gives up.

 

What actually works in the UK

If you want endless free spring onions:

- Buy a packet of proper perennial bunching onion seeds (e.g. “White Lisbon”, “Performers”, “Ishikura”, or “Evergreen Hardy White”) — £1.50–£2 online or in garden centres. One packet lasts years.

- Or buy a small pot of living “bunching onions” or “Welsh onions” from the herb section (Waitrose, M&S, and some garden centres sometimes stock them). Plant them out or in a pot — they regrow forever.

- If you really want to use supermarket ones: cut the green leaves off 2–3 cm above the white part as soon as you get home, stand the white roots in water, and you’ll usually get one more (smaller) harvest in 7–14 days. After that, compost them.

 

Your current jar is basically at the end of its life — it’s done its best! 😄

So the withering isn’t you doing anything wrong; it’s just the nature of the cheap commercial spring onions sold in the UK.