Green onions, often called scallions or spring onions, are popular for home cultivation due to their mild flavor and rapid growth cycle. They belong to the Allium family, offering a delicate onion taste without the full pungency of a mature bulb onion. Their ease of growth and ability to be continuously harvested makes them a highly sought-after, space-efficient crop.
Starting Your Green Onions: Seed vs. Set
The time it takes for a green onion to reach a harvestable size is heavily influenced by the initial planting method. Starting from true seeds is the slowest approach, requiring the plant to go through full germination and initial growth phases. Seeds are typically sown about a quarter to a half-inch deep, and while economical, they involve a longer wait before the first harvest.
A much faster alternative is planting from “sets,” which are small, immature bulbs commercially prepared for planting. Sets are young plants already established in their growth cycle, dramatically reducing the time to maturity. The most immediate method is regrowing green onions from the white root base of store-bought stalks. This technique leverages the existing root structure, allowing the plant to focus immediately on producing new green shoots.
The Growth Timeline: When to Expect Harvest
Starting green onions from seed requires approximately 60 to 80 days until the shoots are ready for the first substantial harvest. Seeds can take up to ten days just for germination, followed by a lengthy “grass stage” where growth is thin and slow. Starting from a set or small transplant significantly shortens this timeline, with a harvest often possible within four to five weeks.
When using the scraps from store-bought green onions, new shoots emerge within a few days of placing the roots in water or soil. These initial shoots can reach a usable size for a light harvest in as little as two to four weeks. This speed highlights the efficiency of utilizing the plant’s established root system.
Maintaining Optimal Growing Conditions
Consistent growth relies on providing the correct environmental conditions. Green onions thrive best in full sun, requiring a minimum of six to eight hours of direct sunlight daily. Insufficient light will slow the production of green tops, extending the wait for harvest.
The soil must be fertile and exceptionally well-drained, ideally a sandy or clay loam enriched with organic matter. Green onions are shallow-rooted, making them susceptible to stress if the soil becomes waterlogged. Consistent moisture is necessary, so the soil should be kept uniformly moist, though never soggy. Maintaining a temperature range between 68ºF and 77ºF is optimal for vigorous growth. A nitrogen-rich fertilizer applied every few weeks promotes the rapid, tender leaf production desired.
Harvesting Techniques for Continuous Supply
The most effective way to ensure an ongoing supply of green onions is to employ the “cut-and-come-again” harvesting method. This technique involves removing only the green, usable portion while leaving the white root base intact in the soil.
To harvest, cut the green stalks about one to two inches above the soil line, ensuring the root structure and the plant’s growth point remain undisturbed. Leaving the root base in place allows the plant to immediately regenerate new foliage using stored energy. After the initial cut, the stalks usually regrow to a harvestable size again within about one week. This continuous cycle allows a small patch of green onions to yield harvests repeatedly throughout the growing season.