The Pantry / Spring Onion
Spring Onion
Allium fistulosum · scallion · green onion · hariyo pyaj · negi
Two vegetables on one stalk.
What it is
Spring onions are alliums pulled young, before the base has swollen into a bulb. They are two vegetables on one stalk: the white end a mild onion that softens in seconds, the green a herb, grassy and faintly sharp, that goes dull and slippery if it sits in heat. Most dishes want the two halves doing separate jobs, so cut them into two piles as you slice.
Where it comes from
Two plants reach the shops under one name. The bunches in British supermarkets are usually ordinary onions, Allium cepa, harvested before they bulb. The plant grown across East Asia and the Himalaya is Allium fistulosum, a perennial that never bulbs and pushes up hollow stalks year after year. In the hill villages it is a kitchen-garden standby, cut through the cold months when little else is green.
What it's called
Spring onion (UK) · scallion and green onion (US) · hariyo pyaj (Nepali) · hari pyaaz (Hindi and Urdu). Allium fistulosum is the Asian perennial, also sold as Welsh onion or negi. Chives are a smaller and much milder plant and will not carry a dish.
In the kitchen
The white goes in early with the ginger and garlic, or raw into a filling where steam will cook it through. The green goes on at the end, off the heat. Momo filling takes both, and the green is what keeps the mince tasting fresh instead of flat. Ema datshi wants them cut on a long diagonal so they hold their bite against the chillies and the cheese. In laphing and the sadeko salads they stay raw and sliced thin, and the sharpness is the point.
What we know about the claims
Useful amounts of vitamin K and vitamin C in the green tops, with the sulphur compounds the onion family is known for. The green is the more nutritious half and the half most often thrown away.
Choosing and buying
Any supermarket in the UK and the US, year round. Look for firm white ends and green that stands up on its own; yellowing or slimy tips mean too long in the chiller. East Asian grocers sell the thicker negi, the same plant grown on and the better buy for long cooking.