Spring onion

Origin & history

The spring onion is botanically the Welsh onion, Allium fistulosum, and comes from East Asia, where it has been grown in China for over two thousand years. It reached Central Europe in the Middle Ages and was kept here as a perennial clump that already produced greens in March, when nothing else stood in the bed. The English name “Welsh onion”, incidentally, has nothing to do with Wales — it comes from Old High German “welsch”, meaning foreign.

Varieties

Two different things are sold under the name spring onion: true Allium fistulosum, which never forms a bulb and keeps a straight white shank, and young-harvested culinary onions (Allium cepa), which swell at the base as soon as you leave them standing. For evenly long shanks choose bunching varieties of the “Ishikura” type; red-skinned sorts look good in a salad but taste very much the same. The perennial Welsh onion is planted once and the clump divided every few years — that gives you a supply every spring without sowing at all.

Care

Very undemanding but shallow-rooted: in dry spells water thoroughly every few days, or the shanks turn tough and the leaf tips go yellow. Because the thin tubular leaves cast practically no shade, every weed wins the race — hoe regularly, but shallowly. If you want a longer white portion, earth up three to five centimetres once the shanks are pencil-thick; feed sparingly, as plenty of nitrogen just makes soft foliage.

What can go wrong

The commonest annoyance is bolting: plants sown very early get their cold stimulus in the still-cold soil, then throw a hard flower stalk and the shank goes woody — sow from mid-March under fleece, or simply start a little later. The onion fly lays its eggs at the neck, the maggot eats out the base and the foliage keels over yellow; a crop-protection net from sowing onwards plus a change of bed from last year is the only reliable answer. In wet weeks downy mildew appears as a grey-violet coating on the tubes — do not sow too densely, keep the position airy and water in the morning at the base so the foliage dries off quickly.

Harvest, storage & kitchen

Harvest the whole plant as soon as the shank is pencil to finger thick; the green is just as usable as the white and gets thrown away far too often. It does not store — wrapped in a damp cloth it keeps two or three days in the fridge and then goes limp. Raw in salads and quark, and into the pan only right at the end or nothing of the flavour survives; from a perennial clump you simply cut the tubes like chives.

Frequently asked questions

When can spring onions be harvested?

Roughly eight to ten weeks after sowing, a little longer for early sowings into cold soil; in the bed that spreads the harvest from early June right through to November. Go by the thickness of the shank rather than the calendar: pencil to finger thickness is the sweet spot.

Are spring onions and salad onions the same thing?

Yes — spring onion, salad onion and scallion all describe the same thing: young onion-family plants with a straight white shank and hollow green tops, usually 30 to 45 cm tall. Only the regional name changes, not the plant.

Can spring onions be left in the ground over winter?

Yes, they are frost hardy and stand through the winter; they push out fresh growth in spring, but soon send up a flower stalk and the shank turns woody. For tender shanks, sow a fresh batch every few weeks from mid-March to early August instead.

Will spring onions grow in a balcony box?

Yes, a box with 15 to 20 cm of soil depth is plenty. A narrow box takes one row, a wide one two rows 20 cm apart; thin the seedlings to 4 cm and give the container a sunny spot. Small containers dry out fast, so water thoroughly and often.