Green onions, often called scallions or bunching onions, are a popular and simple crop to cultivate in a home garden. These plants are typically varieties of Allium fistulosum or immature Allium cepa harvested before a large bulb forms, providing a mild, delicate onion flavor perfect for cooking and garnishing. Their ease of growth and ability to produce continuous harvests makes them a favorite among home gardeners. Successfully cultivating a steady supply depends on understanding the precise timing and method of planting for a quick and flavorful yield.
Optimal Seasonal Timing
Green onions are cool-season crops that thrive in the moderate temperatures of spring and fall, avoiding midsummer heat. The best time to begin planting is in early spring, as soon as the soil is workable, often four to six weeks before the last expected frost date. This early start allows the plants to establish strong root systems before summer temperatures arrive.
For a continuous harvest, employ succession planting by sowing small batches every few weeks. Planting a new row of seeds or sets every three to four weeks from early spring until mid-summer ensures a fresh supply is always ready. This method prevents a glut of green onions all maturing at once.
A second planting window opens in late summer or early fall, about six to eight weeks before the first anticipated frost. Fall-planted green onions will establish themselves before the cold sets in, often overwintering in milder climates and providing a very early spring harvest. In regions with extremely cold winters, a protective layer of mulch can help perennial bunching varieties survive and resume growth as soon as the ground thaws.
Choosing Your Planting Material
There are three options for starting green onions: seeds, sets, or transplants, each offering a different trade-off in speed and cost. Starting from seeds is the most economical option and offers the widest selection of varieties. However, seeds are the slowest method, requiring one to three weeks for germination and 60 to 80 days to reach harvestable size.
Onion sets are small, immature bulbs from the previous season forced into dormancy, providing a faster path to harvest. These bulbs are easy to handle and establish quickly, often yielding green onions faster than seeds. Sets tend to be slightly more expensive, and the variety selection is often limited to generic red, white, or yellow types.
Transplants are small, already-started seedlings, typically six to ten weeks old, offering the quickest harvest since they bypass germination. These are often purchased in bunches in early spring and are planted directly into the garden. While transplants are the most expensive, they provide a reliable head-start, particularly when aiming for a quick early-season yield.
Essential Growing Requirements
Green onions require specific environmental conditions to support rapid, leafy growth. They perform best in a location that receives full sun, meaning at least six to eight hours of direct sunlight daily. They can tolerate some afternoon shade, especially in hotter climates, but maximum light exposure promotes the healthiest, most vigorous foliage.
The ideal soil is a well-draining, fertile sandy loam enriched with organic matter, such as compost. Because they have shallow root systems, the soil must be loose enough for roots to access nutrients without becoming waterlogged, which can lead to rot. A soil pH between 6.0 and 7.0 is preferred, allowing for optimal nutrient absorption.
Consistent moisture is necessary due to the shallow root structure; plants should receive about one inch of water per week, through rainfall or irrigation. The soil should remain consistently moist but never soggy. A layer of organic mulch can help regulate soil temperature and conserve moisture during dry spells. Green onions intended for continuous harvest should be spaced about two inches apart in the row, with rows separated by approximately 12 to 18 inches.
Harvesting Techniques and Continuous Regrowth
Green onions are ready for harvest sooner than bulb onions, typically taking 60 to 80 days from seed, or less time when planted from sets or transplants. There are two main harvesting methods, depending on whether a one-time yield or a continuous supply is desired. For a thicker, more developed white base, the entire plant can be gently pulled from the soil once shoots are about a foot tall.
To ensure continuous production, the preferred method is to cut the green tops using scissors or a knife. The cut should be made about one inch above the white root base, leaving the roots and bulb intact in the soil. This preserved base will stimulate the plant to regrow new shoots, allowing for multiple harvests over the season.
Regrowing Indoors
This regenerative ability allows for regrowing green onions indoors from kitchen scraps. The white root base, usually discarded after cooking, is placed in a glass container with water covering the roots. New green shoots will emerge from the center within a few days and can be harvested repeatedly by trimming the tops. For better long-term health, transition these water-grown bases into a pot of soil after a few harvests.