How to Grow Green Onions

Author: By Beth Sears

Green onions are a garden favorite because they're easy to grow, don't take up much garden space and can be used in so many ways in the kitchen. Sometimes called scallions, these root vegetables are most often planted in the spring. Within weeks you can harvest tender green onions. Green onions are often ready for harvest at the same time as lettuce, peas and other early season vegetables. This cool-season crop can also be grown for a fall harvest.

About Green Onions

A common question is what's the difference between scallions, green onions and full-sized or mature onions? It's mainly maturity. Scallions have no bulb and bright green, crisp tops. Sweet and tender, they're a favorite for eating fresh and in soups and stir-fries. Green onions have small bulbs and bright green, crisp tops. Their flavor may be a little more pungent than scallions. If not harvested at the small bulb stage, the onion bulb will keep growing into larger bulbs used for fresh eating or storage. Larger onions often have a more pungent flavor.

Scallions and green onions are members of the Allium family, which also includes leeks and shallots. Learn more about the difference between onions, leeks and shallots.

In the kitchen, the term scallion and green onion are often used interchangeably. When cooking with scallions and green onions, keep in mind that shallots often have a milder flavor. Because of their flavor and versatility, green onions are popular among home chefs and gourmets. They can be be eaten raw, chopped into salads and salsas, and used in soups and stir-fries.

When to Plant Green Onions

A cool-season crop, onions are most often planted in the spring. You can also grow green onions in the late summer or fall garden. Green onions can be grown from seeds, onion sets or plants.

Growing Green Onions from Onion Sets

Most home gardeners grow green onions from onion sets because it's easy and quick. Onion sets are immature onion bulbs that were harvested the previous year. In the spring, you can find onion sets for sale from mail-order nurseries as well as in hardware stores, garden stores and other retail outlets. When to plant green onions is partially determined by the last spring frost date for your region. Onion sets are usually planted in the spring, about 4-6 weeks before the last frost date for your region. Green onions can often be harvested just 4-6 weeks after planting.

Growing Green Onions from Transplants

For an earlier harvest, gardeners plant onion seedlings in the garden, rather than directly sowing onion seed into the garden. You can either buy onion plants (usually in bundles) from garden stores or mail-order catalogs—or you can start seed indoors and grow your own.

How to Grow Green Onions from Seeds

Onion seed can be started indoors or directly sown into the garden. While growing green onions from seed takes longer and is more labor intensive than growing onions from transplants or sets, it is often more economical. Also, gardeners may have more seed varieties available.

If starting seeds indoors, sow the onion seeds about four weeks before you plan to transplant them to the garden. If sowing onion seed directly into the garden, sow scallion seed as soon as the soil is workable in the spring. Onion seed can also be planted in late summer to early fall for a fall crop.

Where to Plant Green Onions

Onions grow best in full sun and in well-drained, sandy or loamy soil. Green onions can be grown in a sunny location in the garden, raised beds and in containers.

How to Plant Green Onions

Transferring Seedlings from Indoor Sowing

Because indoor seedlings must become acclimated to the outdoors, harden off seedlings before transplanting them to the garden. Over the course of 7-10 days, gradually introduce them to outdoor elements. They may need some cold-weather protection, sun protection and wind protection at first.

How to Grow Scallions

Before planting scallion sets or transplants, make sure the planting bed is free of weeds. Plant onions about 1-2 in. deep and space 2-3 in. apart. Plant in rows 12-18 inches apart. After planting, water well. An all-natural, slow-release fertilizer like Gurney's Onion Food can be side-dressed.

How to Grow Green Onions: Care Guide

Green onions are some of the easiest vegetables to grow as long as their light, soil and water needs are met. Just follow this quick care guide about how to plant green onions.

Sunlight

Green onions grow best in full sun, or six or more hours of direct sunlight daily. If growing green onions in a hot region of the country, they may benefit from afternoon shade.

Temperature

Green onions are cool-season vegetables and can handle light frosts. This makes them ideal for spring and fall gardens.

Soil

Grow green onions and scallions in well-drained, loamy or sandy soil. Soil drainage can be improved by mixing compost into it. If growing green onions in containers or planting in jars, make sure the containers have adequate drainage.

Fertilizer

Onions are heavy feeders and benefit from an all-natural, slow-release fertilizer like Gurney's Onion Food. It can be side-dressed into the soil.

Water

Green onions have average water needs, or require about 1 inch of rainfall weekly. The soil should be kept moist. While you don't want to let them dry out, you also don't want them sitting in wet soil where they are more likely to rot.

Pruning

No pruning is necessary. However, you should weed around the onion plants frequently, as weeds can quickly overtake young green onions.

Pest & Disease control

The onion maggot and several types of rots can affect green onions. Practicing crop rotation, controlling weeds and planting your green onions in well-drained soil helps control these diseases.

Usually deer and rabbit leave onions alone. When growing onions, keep in mind that they are toxic to cats and dogs.

Harvesting Green Onions

Green onions taste the best and have the crispest tops when they are used right after harvest. Most gardeners will harvest scallions and green onions when they need them for salads, relish trays, salsas or other recipes.

Scallions and green onions can be harvested when they are about 6 inches tall or taller. If the soil is moist and loamy, you can pull them from the ground. If the ground is hard, then loosen the soil around the onion before pulling. This keeps the tops from being broken. In many cases you can enjoy a spring and summer harvest of green onions. Keep in mind that green onions tend to become more pungent as they get larger.

While green onions are best used right after harvest, they can be stored in the refrigerator for about a week.

Because they grow quickly and are so versatile in the kitchen, green onions are some of the most rewarding vegetables to grow. You can find a variety of onion plants, seeds and onion sets for sale--or even try the popular Evergreen White Bunching Onion. The 'How to Grow Onions from Seed' video also has some great tips for growing onions.