How to Grow Green Onions: The Complete Guide

Onion spring sibies scallion stem stalk Allium cepa thick bulb common organic plant young vegetables sprout grows ground bio farmer farming agricultural garden fresh, organically grown organic
Photo Credit
Tomas Vynikal
Botanical Name
Allium fistulosum
Plant Type
Sun Exposure

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Planting, Growing, and Harvesting Green Onions

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They’re fresh, fast, and fabulous in salads, stir-fries, quiches, and savory tarts. We’re talking about spring onions, also called scallions. Whatever you call them, they’re great for fitting in wherever there’s space and will give you a harvest of delicious stems in as little as eight weeks.

About Scallions/ Green Onions

Green onions—also known as bunching onions, salad onions, or scallions—are a vibrant and flavorful member of the Allium family. They boast a crisp white bulb with long, emerald green stalks, offering a milder bite compared to their stronger onion cousins. 

Packed with vitamins, minerals, and antioxidants, green onions are a nutritional powerhouse, adding a touch of health to your meals.

They’re also one of those crops that can be sown in late summer to give one of the earliest harvests next spring. So, let’s get growing!

Planting

Sowing Green Onions

Like their bulb-forming cousins, green onions prefer a sunny, open site and fertile, well-drained soil. For best results, grow them in soil that’s been improved with regular additions of well-rotted organic matter such as compost. Check out our guide to composting at home.

These tall, thin plants don’t take up much space, so they’re ideal for containers. Or be opportunistic and grow them between rows of slower-growing vegetables such as parsnips until they need the extra space. Another option is to grow them with carrots, which may help to reduce problems with carrot rust flies.

Start sowing under cover from late winter, then continue outside from spring. Sow short rows every three to four weeks to give a steady supply of oniony stems. Your last sowings, made at the very end of summer using a winter hardy variety, will be ready to harvest early next season. Learn more about vegetables to plant in the late summer.

Sow seeds directly where they are to grow or into containers of potting soil to transplant later on.

Direct Sowing Green Onions

Direct sow seeds into finely-raked soil. Mark out a drill about half an inch (1cm) deep. Use a string line if you prefer neat, straight rows. Additional rows should be spaced about 4in (10cm) apart. If it’s hot and dry, water along the rows before sowing. This creates a cooler environment around the seeds, helping them to germinate.

Sow the seeds thinly along the rows, then pinch the drill closed to cover the seeds. Alternatively, backfill the rows with potting soil. This is useful if your soil isn’t as fine and crumbly as you’d like at sowing time, and also helps rows to stand out clearly from the surrounding soil for the purposes of weeding. Once you’re done, label the rows and water thoroughly.

Sowing in Plug Trays

Sowing into containers helps to make the best use of your available space because you can start seedlings off while a growing crop still occupies the ground. By starting plants off under the protection of a greenhouse, tunnel, or cold frame, you’ll be able to start sowing up to six weeks sooner at the beginning of the growing season.

The easiest method is to use plug trays. Fill your plug trays with a general-purpose potting mix, then firm the mix down into the modules with your fingertips. Sow a pinch of four to eight seeds per module, then cover them with a larger potting mix. Water and keep the potting soil moist as the seedlings appear and grow.

Transplant the clusters of seedlings as soon as they have filled their modules, and you can see roots at the drainage holes. Carefully ease the plugs from the tray, then plant them into prepared soil so each cluster is 2-4in (5-10cm) apart within the row, with rows spaced at least 4in (10cm) apart. Water the young plants to settle the soil around the root ball.

Growing

Direct-sown green onions shouldn’t need much thinning, but if there are any overly thick clusters of seedlings, remove some of the excess to leave about half an inch (1cm) between plants.

Remove weeds as soon as they appear to prevent them from overwhelming your plants. As green onions are shallow-rooting, water in dry weather to speed growth and minimize the risk of plants bolting, or flowering prematurely.

Watch our video. Our college Ben demonstrates how to grow green onions from sowing to harvest.

Harvesting

Green onions are typically ready to enjoy 10 to 12 weeks after sowing, though at the height of the growing season, it can be as soon as eight. Harvest the largest plants first so that those left can continue to grow. This way, you can extend and maximize your harvest.

Store in the refrigerator or slice them up to pack into freezer bags or containers to add to recipes whenever you need a boost of fresh flavor.

a bundle of fresh scallions/green onions on a wooden chopping board.
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Pests/Diseases

As with most of the Allium family, green onions are rarely bothered by pests, but birds can sometimes peck at the emerging seedlings, particularly early on in the season. Cover sown areas and seedlings with row covers if this proves to be a problem.

About The Author

Jennifer Keating

Jennifer is the Digital Editor at The Old Farmer’s Almanac. She is an active equestrian and spends much of her free time at the barn. When she’s not riding, she loves caring for her collection of house plants, baking, and playing in her gardens. Read More from Jennifer Keating