Bunching onions, often recognized as scallions, green onions, or spring onions, are a rewarding crop for the home garden. Unlike common bulbing onions (Allium cepa), bunching onions (Allium fistulosum) are perennial plants that do not form a large, globe-shaped bulb. Instead, they produce clusters of hollow green leaves and slender white stalks. This non-bulbing characteristic allows for a consistent, year-round harvest in many climates, requiring minimal space for maximum yield.
Preparing the Planting Environment
Selecting an optimal location and preparing the soil is the first step toward a successful harvest. Bunching onions thrive when they receive at least six hours of direct sunlight daily, though they can tolerate slight partial shade. Choose a well-draining site, as soggy soil can easily lead to root rot in the Allium family. A slightly acidic to neutral soil pH, ideally ranging between 6.0 and 7.0, is most conducive to healthy growth. Before sowing, incorporate well-rotted manure or compost to increase organic matter, aiding drainage and fertility. Prepare the bed in early spring or late summer for a fall/spring harvest.
Sowing the Seeds
Bunching onion seeds can be started indoors for an earlier jump on the season or directly sown into the garden bed. For an advanced harvest, start seeds indoors six to eight weeks before the last anticipated frost. Seeds germinate best when soil temperatures are consistently between 68 and 75 degrees Fahrenheit.
When sowing, aim for a shallow planting depth of about one-quarter to one-half inch. The seeds can be sprinkled sparingly in rows or planted in small clusters of five to eight seeds, which is a common technique used to produce the classic “bunch” of scallions. Rows should be spaced approximately 12 inches apart to allow for proper light and air circulation.
After covering the seeds with fine soil or compost, water the area with extreme care, perhaps using a mister, to avoid washing the seeds away. Maintaining consistent moisture in the top layer of soil is necessary for germination, which typically occurs within seven to ten days. If starting indoors, transplant the clusters of seedlings outside once they are about four inches tall and the danger of hard frost has passed.
Essential Care After Germination
Once the slender seedlings have emerged, consistent care ensures they develop strong root systems and lush green tops. Bunching onions have shallow roots and require the soil to be kept evenly moist, especially during dry periods, usually requiring about one inch of water per week. Allowing the soil to completely dry out can stunt growth or cause the plants to split prematurely.
If you did not sow in bunches, thinning the seedlings is necessary once they are established and a few inches tall. Thinning involves removing smaller plants to leave the strongest ones spaced about one to two inches apart, allowing for optimal development. While rich, amended soil often provides sufficient nutrients, a light application of a balanced, high-nitrogen fertilizer encourages vigorous leaf growth.
Weeds compete directly with the onions for moisture and nutrients, so keeping the planting area weed-free is important. The Allium family is susceptible to pests like onion maggots and thrips, and diseases such as white rot. Practicing crop rotation and ensuring good air circulation minimize the risk of these issues.
Harvesting for Continuous Yield
The appeal of bunching onions lies in their “cut-and-come-again” harvesting method, which allows for repeated yields from the same plant. Harvesting can begin once the green stalks are approximately six to eight inches tall, providing a mild and tender flavor.
To ensure continuous regrowth, cut the green stalks one to two inches above the soil line, leaving the white root base intact in the ground. The remaining root system and the small white base contain the growth point that will quickly regenerate new green leaves, often within one to two weeks.
If you prefer to harvest the entire plant, loosen the soil around the base with a fork or trowel before gently pulling it out. For perennial production, only cut the greens and leave a portion of the cluster untouched to continue growing year after year.