Spring onions (scallions or green onions) are members of the Allium family, harvested for their mild flavor before the bulb fully matures. Their tender white base and hollow green tops are widely used in cooking, making them a desirable crop for home gardeners. Determining the precise harvest time is important, as it directly impacts the plant’s texture and mildness. Unlike bulb-forming relatives, spring onions are gathered while they are still actively growing, not after the tops die back.
Timing the Initial Harvest
The time required for spring onions to reach harvestable size depends primarily on the planting method. When grown from small, immature bulbs known as sets, the plant establishes quickly, allowing for an early harvest. This method can yield usable spring onions in as little as three to four weeks after planting.
Growing spring onions from seed requires a longer period to mature enough for consumption. Gardeners should anticipate approximately six to eight weeks before the first harvest is ready from a seed-sown crop. Environmental factors like soil temperature and consistent moisture influence growth speed, but this window serves as a reliable guideline. Harvest the plants while they are young and tender, before they form a large, pungent bulb.
Recognizing Readiness Cues
Beyond the general timeline, the physical characteristics of the plant indicate readiness. The most straightforward cue is the thickness of the white stalk just above the soil line. A ready spring onion measures about the width of a pencil, or slightly less, indicating a good balance of tenderness and flavor.
The height of the plant is another reliable sign, with many varieties ready when they reach about six to eight inches tall. At this stage, the green tops should be upright, hollow, and vibrant green. If the foliage begins to turn yellow or the plant develops a larger, rounder bulb at the base, it is moving past the optimal harvesting window. Harvesting before these changes ensures the mildest flavor profile.
Harvesting Techniques for Continuous Use
Gardeners have two main options for harvesting spring onions, each affecting future production differently. The first method involves pulling the entire plant from the soil, resulting in a one-time harvest. This approach provides the full length of the white stem and roots, but removes the plant entirely, requiring fresh planting for the next crop. Gently loosening the soil before pulling helps prevent the tender stalk from breaking.
The second, more sustainable approach is the “cut and come again” method, which allows for multiple harvests from a single plant. To execute this technique, use sharp scissors or a knife to snip the green tops. Leave approximately one to two inches of the white base and the root system intact in the soil.
Leaving the root system and base allows the spring onion to regenerate new green shoots. This regrowth ensures a continuous supply of fresh greens throughout the growing season without the need for immediate replanting. Consistent watering and feeding after cutting supports the plant’s recovery and encourages the production of new leaves for subsequent harvests.