How to Grow Green Onions: From Seeds & Regrowing

Green onions (Allium fistulosum) bring the flavor of onions without the long wait in the garden or the peeling in the kitchen. Although the terms scallions, green onions, and spring onions are often used interchangeably to mean any onion harvested before the bulb fully forms, they are actually distinguished from one another based on their age:

• Scallions: Youngest form; clump-forming onions with very thin bulbs (not bulbed, narrow like the stem); the leaves and bulbs are good for eating and are often more tender and mild than green onions
• Green onions: Slightly older than scallions; might have a very small bulb beginning to form; the leaves are good for eating
• Spring onions: Oldest form of young onions; the bulb is round and smaller than a quarter; the leaves are edible but much stronger in flavor

Green onions are perennials that form long, dark green, tubular leaves that change to white bulbs underground, despite being considered "bulbless" onions. The leaves can reach up to 3 feet in height but are typically harvested when they're around a foot tall. The stalk and the bulb are prized for their bright yet mild onion flavor and can be eaten raw or cooked.

Green onions have a rapid growth rate. It takes about 60 to 80 days to grow green onions, from seeding to harvest. They are typically planted in the spring, you can start seeds indoors in March or April and transplant those sprouts in the ground in May once the ground temperature is about 50 degrees Fahrenheit. If you have pets, it's important to note that green onions can be toxic to them.

How to Plant Green Onions

When to Plant

Green onions are best planted in the spring for a summer harvest. In climates where green onions grow well as perennials, they can be harvested year-round without replanting.

Selecting a Planting Site

If planting in the ground, choose a sunny spot in the garden with well-draining soil. They also grow well in containers. Be sure to keep weeds away from green onions to avoid competition for soil moisture and nutrients. A layer of mulch can help keep weeds down.

Spacing, Depth, and Support

Plant seeds about 1/4 inch deep, and plant seedlings at the same depth they were growing in their previous container. Space plants roughly 2 to 3 feet apart in rows that are 1 to 2 feet apart. A support structure typically isn’t necessary.

Green Onions Care

Light

These are leafy vegetables that can handle a bit of shade. But they do best and remain healthiest in full sun, meaning at least six hours of direct sunlight on most days.

Soil

Green onions prefer a rich, sandy loam that has sharp drainage and a slightly acidic to neutral soil pH. Add organic matter, such as compost, to the soil around 6 to 8 inches deep when planting to boost growth.

Water

Green onions have a shallow root system, so regular watering and/or rainfall is a must as soon as the soil starts to dry out. However, do not let the plants sit in wet soil, leading to rot and other diseases. The soil should be consistently moist but not soggy. A drip irrigation system will keep roots well-watered while protecting foliage from excess moisture, which also can cause disease.

Temperature and Humidity

Green onion seeds generally need a soil temperature of at least 45 degrees to germinate, though warmer is better. The plants like growing temperatures between 68 and 78 degrees. They do not mind humid conditions, as long as they have good drainage to prevent rot and other diseases.

Fertilizer

Give your plants a balanced fertilizer, following label instructions. Fertilizer that is high in nitrogen, such as fish emulsion, will keep them green and growing.

Pollination

Green onions self-pollinate, though it's best not to let them flower as this can impact the taste of the leaves.

Types of Green Onions

There are several green onion varieties, including:

• 'Guardsman': This variety is ready for harvesting within 60 days of planting.
• 'Nabechan': This is a Japanese variety prized for its flavor.
• 'Red Beard': This one features purple-red stalks and is quick and easy to grow.
• 'Tokyo Long White': This is another flavorful perennial variety with long, slender stalks.

Green Onions vs. Garlic

The leaves of a garlic plant can sometimes be mistaken for green onions. They’re both tall, narrow, and green. However, a telltale difference is the garlic leaves will smell faintly like garlic, while green onion leaves will smell like onion. The garlic leaves are also typically thicker than green onion leaves.

Harvesting Green Onions

Green onions are tender and mild when they are young. You can start harvesting as soon as the plants reach about 6 to 8 inches tall and are as wide as a pencil, simply cutting off the leaves you need for cooking. Harvest the whole plant by pulling it out of the soil, wash it, and use as desired, fresh or cooked in dishes. The fresh leaves will keep in the refrigerator for about a week. If you are growing green onions as a perennial, it is recommended that you avoid harvesting them during the first season. This allows the plant to become established and produce a more bountiful crop. Then, trim off the leaves as needed.

How to Regrow Green Onions

You can regrow green onions if you keep the root ends. You can also grow green onions from store-bought green onions. Slice off the ends of the bulbs, and keep the roots attached. Stand the root ends down in a small jar. Add water to cover the roots, but leave the tops above water. Put it in a bright window, replenishing water as the water reduces or evaporates. Green shoots will begin to grow from the tops in a few days. Keep the roots underwater and change the water once a week.

You can't leave green onions in water perpetually since they don't have the necessary nutrients to thrive in only water. Once the shoots are at least 4 inches long, plant the root end in a pot or the ground, using good-quality potting soil. If using green onions for cooking, snip leaves as needed. You can cut the leaves to the ground; they will grow back. You can get at least three to five harvests from one bulb.

If you pull the bulb and keep regrowing it with water or divide the roots each spring, you can keep regrowing your green onion crop perpetually. Green onions are winter hardy and will spur new growth in early spring.

How to Grow Green Onions in Pots

Green onions grow well in pots, as their root system is fairly small. Make sure the pot has drainage holes. Any container material will do, though an unglazed clay that allows excess soil moisture to escape through its walls can help to prevent root rot from overwatering. Be sure to empty the container saucer immediately if it fills with water.

Propagating Green Onions

Green onions are often propagated by division when they are grown as perennials. Spring is the best time to divide a mature plant. Here’s how:

1. Simply dig up a clump, leaving the roots as intact as possible.
2. Gently pull apart the roots to create two or more sections, depending on how large the plant is.
3. Replant each section in a suitable growing site, patting the soil around it and watering well.

How to Grow Green Onions From Seed

You can start seeds indoors about eight to 10 weeks before your projected last frost date, or direct sow in the garden once the threat of frost has passed. Sow the seeds about 1/4 inch deep. As with other onions, germination can be slow and poor. The most important element green onion seeds need is constant moisture, which makes starting them indoors where you can keep an eye on them a good choice. Seedlings should emerge in one to two weeks. Once you have growth, thin the seedlings to about 2 inches apart. For a continual harvest, succession-plant new crops every three to four weeks.

Potting and Repotting Green Onions

Use a quality, well-draining, organic potting mix when planting green onions in a container, and water at the time of planting to evenly moisten the soil. If you use a large enough container and regularly harvest your green onions to prevent them from becoming overgrown, you likely won't have to repot your plant.

Overwintering

If you are growing green onions as perennials, apply a thick layer of mulch in the late fall for cold-weather protection. Remove it in the spring when the soil has warmed. You will get an earlier crop this way.

Common Pests and Plant Diseases

There are several pests that can cause issues for green onions. Watch out for cutworms, onion maggots, onion nematodes, slugs, thrips, aphids, and allium leaf miner. If you start noticing problems, such as damaged foliage or lack of healthy growth, planting your next crop in a different area of the garden can help. Moreover, mildew, leaf spots, and rust can occur, especially in improper growing conditions. Make sure the plants are getting adequate sunlight and moisture.

From: thespruce