Spring onions belong to the onion family and look like thin leeks, with tiny bulbs and long, hollow green tops. The only preparation they require is to be trimmed at either end. They are milder than mature onions and very versatile, eaten raw and cooked. The term shallots is sometimes used for spring onions as naming conventions vary in different locations.
Spring onions are harvested while the leaves are still fresh and green, and the bulb is either undeveloped or very small in diameter.
Postharvest storage temperature
The shoots continue to elongate after harvest. Spring onions should be cooled to 0°C within several hours after harvest in order to prevent elongation and to minimise wilting and decay.
Controlled atmosphere storage
No commercial benefit has been identified for onion varieties with long storage potential.
Ethylene may encourage growth of decay-causing fungi.
Spring onion plants have a high leaf area and consequently are very susceptible to postharvest weight loss. They benefit from light misting, especially while on display during marketing. Without supplemental humidification, spring onions will rapidly lose their crispness and start to show signs of wilting. Spring onions should be stored at 95–98% relative humidity.
Disease & infection
Spring onions are susceptible to bacterial diseases common to allium species including pink root, white rot, downy mildew, purple blotch, onion maggot and thrips. To avoid or minimise these problems, do not plant shallots in the same soil where other alliums have been grown in recent years, plant only clean, healthy plants or bulbs, and practice good sanitation.
Chop spring onions early in your preparation and set aside for a few minutes to enhance flavour. Add to the end of cooking to maximise flavour and health benefits.