Growing Salad Onions from Sowing to Harvest

, written by Benedict Vanheems gb flag

Salad onions, aka spring onions, scallions, or green onions

They’re fresh, fast and fabulous in salads, stir-fries, quiches and savory tarts. I’m talking about salad onions, also known as scallions, spring onions or green onions. 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.

Salad onions are 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 on and grow some!

Sowing Salad Onions

Like their bulb-forming cousins, salad 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.

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, where they may help to reduce problems with carrot rust fly.

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.

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

“Sowing
Sow salad onions every few weeks for a continuous supply

Direct Sowing Salad 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
Sowing in plug trays under cover enables an early start to the season

Sowing Salad Onions in Plug Trays

Sowing into containers helps to make the best use of your available space because you can start seedlings off while the ground is still occupied by a growing crop. And 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 more potting mix. Water and keep the potting soil moist as the seedlings appear and grow on.

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.

“Planting
Transplant clusters of seedlings when they have filled their plug tray cells

Caring for Salad Onions

Direct sown salad 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. Salad onions are shallow-rooting, so water in dry weather to speed growth and minimize the risk of plants bolting, or flowering prematurely.

Salad 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.

“Sliced
Fast-growing salad onions are ready for harvest in just 8-12 weeks

Harvesting Salad Onions

Salad 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 your salad onions 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.

Salad onions are reliable, versatile and downright delicious – I wouldn’t be without them, that’s for sure! What about you? You can let us know down below.

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