A Guide on How to Grow Spring Onions

What makes spring onions particularly brilliant for British gardens is their adaptability to our unpredictable weather. Unlike their bulbing cousins, they don’t need months of consistent sunshine to produce something worthwhile. You can sow them almost year-round with the right approach, harvest them at whatever size suits your cooking, and squeeze them into the tiniest growing spaces. I’ve tucked them between slower-growing brassicas, used them as gap-fillers in containers, and even grown them purely for their green tops when I’ve run out of chives.

This guide covers everything I’ve learned on how to grow spring onions reliably in British conditions, from selecting the right varieties for different seasons to dealing with the few problems that might actually trouble them. Whether you’re working with a proper vegetable plot or just a couple of window boxes, you’ll find these techniques straightforward and effective. For more on this, see our guide on from seed to harvest: my guide to growing perfect salsify.

How to Grow Spring Onions

Getting started with spring onions requires minimal investment, which is part of their appeal. I’ve found that success depends more on good timing and soil preparation than fancy equipment or expensive materials.

Essential Growing Materials

The basics are straightforward. You’ll need spring onion seeds, naturally, and I’d recommend buying fresh stock rather than using packets that have been sitting in a drawer for years. Germination rates drop noticeably after about two years, though I’ve had reasonable success with three-year-old seeds when nothing else was available.

For soil, anything reasonably fertile works well. I’ve grown excellent spring onions in standard multipurpose compost, homemade garden compost mixed with topsoil, and even clay soil that I’d improved with organic matter over previous seasons. They’re not particularly fussy, though they do appreciate good drainage. If you’re container growing, any decent multipurpose compost will do the job, preferably peat-free if you’re trying to reduce environmental impact. You might also find from seed to harvest: growing chinese cabbage successfully helpful.

Containers need drainage holes, obviously, and should be at least 15cm deep. I’ve used everything from purpose-built vegetable planters to recycled food containers, and they’ve all worked fine. Width matters more than you might think because spring onions are typically grown quite close together. A container 30cm wide will give you space for a decent crop.

Optional but Useful Items

A few additional bits can make life easier. Horticultural fleece protects early sowings from late frosts and can extend your growing season at both ends. I keep a roll handy because it’s useful for dozens of crops, not just spring onions.

A garden rake helps create the fine, level surface that makes sowing easier, particularly if you’re growing in open ground. For container growing, a hand fork does the same job. Labels are surprisingly important because it’s remarkably easy to forget what you’ve sown where, especially if you’re trying multiple varieties or doing succession sowings.

Some gardeners swear by cloches for early sowings. I’ve used cut-off plastic bottles over individual rows, which works well enough, though proper cloches give better results if you’re serious about early crops. They’re not essential, though, just helpful.

Step-by-Step Instructions

Growing spring onions successfully is mostly about timing your sowings right and keeping them watered during dry spells. The actual growing process is straightforward once you understand the basics.

Preparing Your Growing Space

Start by sorting out your soil or compost. If you’re sowing direct into garden soil, remove any weeds and rake the surface until it’s reasonably fine. You don’t need a perfect seedbed like you would for carrots, but removing large clods makes sowing much easier. I work in some garden compost or well-rotted manure if the soil hasn’t been fed recently, though spring onions aren’t heavy feeders so this isn’t critical.

For containers, fill them with compost to about 3cm below the rim, firming it gently with your hands. I’ve learned not to compress it too much because overly compacted compost drains poorly and makes it harder for roots to penetrate. Water the compost thoroughly before sowing rather than afterwards, which prevents seeds being washed into clumps.

Timing matters considerably with spring onions. From March through to August, you can sow outdoors without protection and expect decent results. Earlier sowings from February need fleece or cloche protection, whilst autumn sowings in September work well in milder regions but may need protecting in colder areas. I’ve had good results with winter-hardy varieties sown in September, which overwintered successfully in my Hampshire garden and provided early spring harvests.

Sowing Your Seeds

The traditional method involves creating shallow drills about 1cm deep. I use a bamboo cane or the edge of a rake to make these, spacing rows roughly 15cm apart if I’m doing multiple rows. Scatter seeds thinly along the drill, aiming for one seed every centimetre or so. This sounds precise, but honestly, I just sprinkle them fairly sparsely and it works fine.

Cover the seeds by raking soil back over them or, in containers, sprinkling a thin layer of compost on top. Firm the surface gently with the back of your hand or a flat piece of wood. Water using a fine rose on your watering can because a strong jet can displace the seeds.

An alternative approach that I’ve used successfully is broadcast sowing, particularly in containers or small raised beds. Scatter seeds fairly evenly over the prepared surface, aim for them landing roughly 1-2cm apart, then cover with a thin layer of compost or sieved soil. This method gives you a dense patch of spring onions that you harvest by gradually thinning, taking the largest ones first.

Caring for Growing Plants

Spring onions need surprisingly little attention once they’re up and growing. The main requirement is consistent moisture, particularly during dry weather. I check containers daily during warm spells because they dry out quickly. Garden-grown plants need watering weekly if there’s no rain, more often in hot weather.

Weeding matters more than you might expect. Spring onions have thin, upright foliage that doesn’t shade out weeds effectively, and they don’t compete well with vigorous weeds. I hoe carefully between rows or hand-weed around plants, being cautious not to disturb the shallow roots. Keeping on top of weeds early makes life much easier later.

Feeding isn’t usually necessary for spring onions because they grow quickly and don’t form large bulbs. If your soil is particularly poor or you’re growing in containers, a liquid feed every couple of weeks helps maintain good growth, but I’ve grown plenty of excellent crops without any supplementary feeding at all.

Harvesting Your Crop

This is where spring onions really shine because you can harvest them at almost any size. I start pulling them when they’re about pencil thickness, though some people prefer them thinner. Insert a hand fork beside the row and lever gently to loosen the soil, then pull plants individually by grasping them close to the base.

For broadcast-sown patches, I simply pull the largest ones as needed, which gives the remaining plants more space to develop. This approach means you can harvest from the same patch for several weeks, though eventually, the quality declines as plants get older and thicker.

Harvest in the morning if possible, especially during hot weather, when plants are fully hydrated. They store better and stay crisper this way. I’ve found they’ll keep in the fridge for a good week if you trim off any damaged outer leaves and pop them in a plastic bag.

Common Mistakes to Avoid

Despite spring onions being generally cooperative, I’ve made plenty of errors over the years, and I’ve seen other gardeners struggle with avoidable problems.

Sowing Problems

The most frequent mistake is sowing too thickly. I’ve done this more times than I care to admit, particularly when trying to use up old seeds. Overcrowded seedlings compete for light, water, and nutrients, resulting in thin, weak plants that never develop properly. If you do oversow, thin them ruthlessly when they’re a few centimetres tall, removing the weakest seedlings to leave plants roughly 2cm apart.

Another common error is sowing too deep. Spring onion seeds are small and lack the energy reserves to push through heavy soil covering. I’ve had poor germination from sowings that were covered with more than 1.5cm of soil, particularly in heavier clay soils that crust over when dry. Shallow sowing, properly firmed and kept moist, gives much better results.

Timing mistakes happen frequently too. Sowing too early without protection leads to slow germination and increased pest problems. I tried February sowings without fleece during a cold spring and lost half the crop to slugs before it even got going. Similarly, sowing too late in autumn means plants don’t establish before winter, making them vulnerable to frost damage.

Growing and Harvesting Errors

Inconsistent watering causes several problems. Severe water stress makes spring onions hot and harsh-tasting, whilst fluctuating moisture levels can cause splitting or trigger premature bolting. I’ve ruined crops by neglecting containers during hot weather, returning from a weekend away to find them effectively unusable.

Leaving plants too long before harvesting is another issue. Spring onions that sit in the ground for months become increasingly tough and strongly flavoured. They may also start forming small bulbs at the base, which isn’t necessarily bad but changes their character. I prefer harvesting them youngish and sowing successionally rather than leaving them to become overgrown.

Finally, pulling plants without loosening the soil first often results in broken stems, leaving the base in the ground whilst you’re left holding just the green tops. This is particularly common in heavier soils or during dry weather when the ground is hard. Always loosen them first with a fork or trowel.

Expert Tips

After growing spring onions in various locations across southern England, I’ve picked up several techniques that consistently improve results.

Succession Sowing Strategy

Rather than sowing a large batch all at once, I sow short rows or small containers every two to three weeks from March through July. This approach provides a continuous supply of young, tender spring onions rather than a glut followed by a gap. Each sowing takes five minutes, and you’re never overwhelmed with more than you can use.

I’ve found that sowing little and often also reduces waste. Spring onions don’t store particularly well compared to bulbing onions, so having them reach harvest size gradually makes much more sense for home growing. My current system involves four sowings between March and June, which keeps me supplied from May through September.

Variety Selection

Choosing the right variety for the season makes a noticeable difference. Summer varieties like ‘White Lisbon’ grow quickly and work brilliantly for spring and summer sowings but aren’t particularly hardy. For autumn sowings that will overwinter, I use specifically bred winter-hardy varieties that tolerate frost and cold, wet conditions.

Red-stemmed varieties add visual interest and have a slightly milder flavour than white types. I grow both, using red ones primarily in salads where their colour shows well. The growing requirements are identical, so it’s purely a matter of preference and availability.

Companion Planting Benefits

Spring onions work well interplanted with various crops. I’ve grown them successfully alongside carrots, where their onion scent may help confuse carrot root fly, though I can’t definitively prove this helps. They definitely work well between slower-growing brassicas, using space that would otherwise be empty and getting harvested before the larger plants need the room.

In containers, I’ve combined spring onions with lettuce and radishes, all of which have similar water requirements and harvest at different rates. This intensive growing approach maximises the use of limited space, particularly valuable if you’re restricted to patio growing.

Dealing with Bolting

Bolting, when plants prematurely produce flower stems, happens occasionally with spring onions, usually triggered by temperature fluctuations or water stress. Once a plant has bolted, the stem becomes woody and largely unusable, though you can still harvest and use the green tops.

I’ve found the best prevention is consistent watering and choosing appropriate varieties for the season. If bolting does occur, harvest affected plants immediately and use what you can. The remaining plants in the row often continue growing normally, so you don’t necessarily lose the entire crop.

Frequently Asked Questions

Can you regrow spring onions from supermarket scraps?

Yes, you absolutely can, and it’s surprisingly effective for short-term production. When you buy spring onions, leave about 3-4cm of the white base with roots attached. Pop these in a glass of water on a windowsill, changing the water every couple of days. The green tops regrow within a week or so, and you can snip them off as needed. I’ve kept the same roots going for several weeks this way. For longer-term production, plant the roots in compost about 2cm deep, where they’ll establish properly and keep producing. They won’t last indefinitely because they eventually exhaust their energy reserves, but you’ll get several harvests before they decline. This method works brilliantly if you’ve got limited growing space or just want to experiment before committing to growing from seed.

Why are my spring onions thin and straggly?

Several factors cause this problem, but overcrowding is usually the main culprit. When spring onions are sown too thickly and not thinned, they compete intensely for resources and produce weak, thin stems rather than the plump stalks you want. Inadequate light also causes this issue, particularly with indoor or shaded sowings where plants stretch towards available light. Poor soil fertility can contribute, though spring onions aren’t especially demanding. I’ve found that thinning seedlings to about 2cm apart makes an enormous difference to final size. If your plants are already established and looking thin, try feeding with a balanced liquid fertiliser every week or two. Make sure they’re getting at least four to five hours of direct light daily, more if possible. In my experience, properly spaced plants in decent compost with adequate water rarely have this problem.

What’s the difference between spring onions and salad onions?

Honestly, they’re the same thing, just different names used in different regions or contexts. You might also see them called scallions, green onions, or bunching onions, depending on where you are or which seed catalogue you’re reading. They’re all varieties of Allium fistulosum or young plants of regular onions (Allium cepa) that are harvested before the bulb develops. Some varieties are specifically bred for their mild flavour and uniform appearance, whilst others are just standard onions pulled young. Welsh onions are a related species that’s grown similarly but tends to be hardier and more perennial in nature. For practical growing purposes, treat them all the same. The naming confusion is purely linguistic rather than horticultural, so don’t worry too much about getting the terminology exactly right.

Can spring onions survive winter outdoors?

It depends entirely on your location and the variety you’re growing. Standard spring onion varieties like ‘White Lisbon’ struggle with hard frosts and prolonged cold, wet conditions. However, winter-hardy varieties specifically bred for autumn sowing cope remarkably well with British winters, particularly in milder regions. I’ve successfully overwintered autumn sowings in Hampshire with minimal protection, though plants didn’t grow much during the coldest months. They survived and resumed growth in early spring, providing harvests weeks before spring-sown crops. In colder northern regions or exposed sites, you’ll get better results with fleece protection or cloche covering during the harshest weather. Container-grown plants are more vulnerable because their roots experience greater temperature fluctuations, so I’d recommend moving these somewhere sheltered or providing extra protection. If you’re unsure about your local conditions, try a small test sowing with protection to see how they fare.

How long do spring onions take to grow from seed?

Most varieties reach harvestable size within eight to twelve weeks from sowing, though this varies considerably with temperature, variety, and growing conditions. Spring and early summer sowings in warm soil grow fastest, sometimes reaching pencil thickness in just seven weeks. Autumn sowings are much slower, particularly if they’re overwintering, and may take four to five months before they’re ready. Container-grown plants tend to develop slightly faster than those in open ground because the compost warms more quickly. You can start harvesting spring onions at whatever size suits your needs, though I find they’re most useful once they’re at least the thickness of a pencil. I’ve pulled them much smaller when desperate for a garnish, and I’ve left them to develop quite thick stems when I wanted something more substantial for stir-frying. The beauty of spring onions is this flexibility, so don’t feel obliged to wait for some perfect size. Start checking them from about six weeks after sowing and harvest when they look right to you.

Do spring onions need feeding during growth?

Generally speaking, no, spring onions don’t require regular feeding if you’re growing them in reasonable soil or fresh compost. They’re quick-growing crops that are harvested before they’ve had time to deplete soil nutrients significantly. I’ve grown excellent crops without any supplementary feeding in garden beds that were prepared with compost the previous autumn. However, there are situations where feeding helps. Container-grown plants benefit from occasional liquid feeding, perhaps every two weeks, because containers have limited nutrient reserves. Very poor soil might need improvement before sowing or feeding during growth to achieve good results. If your plants look yellowish or are growing very slowly despite adequate water and light, a balanced liquid feed will likely perk them up. I use diluted general-purpose vegetable feed when I do feed them, though they’re not fussy about specific formulations. Avoid high-nitrogen feeds that encourage excessive leaf growth at the expense of stem development. The key is not overfeeding because spring onions don’t need the intensive nutrition that heavy feeders like tomatoes or courgettes require.

Conclusion

Growing spring onions successfully really comes down to three things: sowing little and often for continuous supply, keeping them consistently watered, and harvesting while they’re still young and tender. They’re one of the most rewarding crops for beginners because results come quickly and the techniques involved are straightforward.

I’ve found them invaluable for filling gaps in crop rotations, making use of container space, and providing fresh harvests almost year-round with proper variety selection and timing. The satisfaction of pulling fresh spring onions from your own garden, whether that’s a proper allotment or just a window box, never quite wears off.

Start with a small sowing this growing season and see how you get on. You’ll likely find, as I did, that spring onions become a permanent fixture in your garden because they’re simply too useful and too easy to justify not growing them.

Author: Megan Walker

Megan focuses on seasonal food, kitchen garden growing, and how households can reconnect with where their food comes from. Her writing blends practical growing advice with ideas for cooking and eating in season. With a passion for fresh ingredients and sustainable living, Megan’s articles help readers make the most of local produce while supporting British farms.