Discover how to grow green onions from seed with this guide, packed with tips and tricks for a bountiful harvest.
I remember back when I was a young girl, I would pick green onions from my mother's garden and snack on them as I played outside (yes, I was a weird kid!) I still love munching on those stalks today, although usually to add flavor to a dish rather than raw!
Green onions grow fast and don’t take up much space in the garden, making it a satisfying crop that's not too fussy. They're also adaptable to container gardening, which is how I plan to grow them this year.
It’s easy to plant a few green onion seeds every few weeks in spring and summer for months of harvesting. That way, you'll always have some on hand for dinner (or a light snack if you're into that sort of thing!)
Let's get growing!
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Things to Know about Growing Green Onions
Also called scallions and bunching onions, green onions typically mature 60 to 90 days after germination. You can start them indoors or direct sow them in garden soil. The plants can be spaced close together but need full sun and ample water to thrive.
Many green onion types do not form round bulbs like regular onions. Instead, they grow slender white or red stems underground with narrow, tall leaves. However, some varieties, such as spring onions, form small bulbs with even more flavor.
Green onions grow best in mild temperatures and loamy ground with good drainage. Unfortunately, they don’t compete well with other vegetation, so regular weeding is necessary.
Green Onion Varieties
You can find dozens of green onion varieties differing in leaf size, bulb color and shape, flavor and spiciness, days to maturity, heat and cold tolerance, and pest resistance.
- ‘White Lisbon’ is an old, reliable cultivar that grows well in many soil types and climates.
- ‘Long White Evergreen,’ an heirloom with 12-inch plus greens and a crisp, mild flavor.
- ‘Ishikura’ has tender, extra-long leaves up to 2 feet tall. Heat and cold tolerant and popular in Asian cuisine.
- ‘Santa Claus’ has red below-ground stems that deepen in color as temperatures drop.
- ‘Red Baron Bunching’ produces burgundy-red stems that bulb up if left to grow, producing red mini-onions, perfect for pickling.
- ‘Italian Red of Florence’ has bright-red, oblong, slightly bulging lower stems, delicious raw and cooked.
This year, I'm growing Evergreen White Nebuka green onions from seed. Here's what they look like:
How to Plant Green Onion Seeds
Green onion seeds sprout in a wide temperature range between 45 to 80°F, taking between 7 and 14 days to germinate. Onion seeds are only viable for one year, so always use fresh seeds.
Starting Green Onion Seeds Indoors
You can start seeds in flats or seed trays indoors and keep them under artificial light for 4 to 12 weeks before transplanting after the frost season ends. Depending on your growing conditions, seeds started in early April can be ready for transplanting at the start of May.
- Fill trays of small cells or pots with a high-quality seed starting soil mix.
- Sow several seeds per cell or scatter about 20 seeds on the soil surface of a 6-inch pot.
- Cover the seeds with about ¼ inch of soil.
The seeds do not need light to germinate, but bottom heat from a heat mat can speed up sprouting. Give the seedlings bright sunlight or artificial light all day as soon as they emerge.
I planted all my vegetable seeds in these small peat pots, and covered them with plastic wrap to retain moisture. I'll remove each pot from the plastic wrap once the seeds sprout.
After four weeks, fertilize the seedlings with a half-strength liquid fertilizer every week until you transplant. Also remember to raise your grow lights as your plants get taller. Mine have scorched tips from touching the hot lights!
Direct Sowing Green Onion Seeds Outdoors
Once the ground is able to be worked in spring, you can plant your green onion seeds outdoors. Direct sow into well-worked soil containing ample good-quality compost or aged manure.
- Create shallow furrows in rows about 18 inches apart.
- Sow seeds densely in the rows and cover with ¼ to ½ inch of soil.
- Keep the ground evenly moist as the seeds germinate.
- Thin the seedlings to 1 inch spacing when they are a few inches tall.
Growing Green Onions in the Garden
Green onions need at least six hours of direct sunlight, but full sun exposure is best. They need fertile soil that drains readily, but the roots are shallow, so you can incorporate compost or other organic matter into the top six inches to prepare the site.
Avoid planting green onions in areas with perennial grasses like Bermuda or quack grass because the deep, tough grass roots hamper effective weed control around the onions. Raised beds can help separate your green onion plants from encroaching grasses.
When transplanting seedlings started indoors, take the onions out of the container and gently separate the plants from each other. Onions don’t mind having their roots handled or left out of the soil for a short time during transplanting.
Set the seedlings about two inches deep and 1-4 inches apart. Carefully backfill soil around the plants, and water the area immediately after planting.
In more northern areas, you can plant green onions in spring for harvesting in summer. In warmer growing regions, you can plant them in spring and again in fall and overwinter them for an early crop the following year.
Caring for Green Onion Plants
Regularly pull weeds or cut them at the soil surface to avoid disturbing the green onion roots. As the plants grow and produce more shade, they need less weeding, but keeping weeds down early is vital for rapid growth.
Keep the garden bed or pot evenly moist as the plants grow. Setting up your garden beds on drip irrigation is an efficient way to keep all your plants watered without having to drag out the hose every day!
Harvest green onions by loosening the dirt around the plants using a narrow trowel and then gently pulling the leaves of individual plants straight upward to avoid breaking the stem below the soil surface.
Now that you know how to grow green onions from seed, you may never need to buy them at the grocery store again! Trust me, the satisfaction of plucking those fresh, flavorful stalks straight from your garden is truly unbeatable!