How to Grow Spring Onions in the UK: Complete Growing Guide
Spring onions (salad onions or scallions) are quick-growing, versatile vegetables perfect for UK gardens. With their mild flavour and crisp texture, they're ideal for salads, stir-fries, and garnishes. Easy to grow and ready to harvest in just 8-12 weeks, spring onions can be sown almost year-round for continuous harvests. This comprehensive guide will show you how to grow spring onions successfully.
Watch The Spring Onions Growing Video
Spring onions are useful for repeat sowings, containers and quick salad harvests when the main beds are already busy.
Use the how-to page for sowing depth, spacing and harvest notes, then check the timing page before succession sowing.
Not sure when to sow? See our When to Plant Spring Onions UK →
Founder & Head Grower, SoilCommander · RHS Level 2 · 12+ years growing in Yorkshire
I've been growing vegetables on my Yorkshire allotment and raised beds since 2012. Everything I write is based on what I've actually grown, failed at, and eventually got right in a real UK climate.
Quick Growing Facts
- Sowing Time: March to September (year-round with protection)
- Harvest Time: 8-12 weeks after sowing
- Growing Time: 8-12 weeks
- Difficulty: Very easy
- Position: Full sun to partial shade
When to Sow Spring Onions
Spring onions can be sown almost continuously for year-round harvests:
- Outdoor sowing: March to September for spring, summer, and autumn harvest
- Under cover: September to February in greenhouses, polytunnels, or cold frames for winter and early spring harvest
- Succession sowing: Sow small batches every 2-3 weeks for continuous supply
- Hardy varieties: Use winter-hardy varieties for autumn sowings
Soil Preparation
Spring onions are adaptable but prefer well-drained, fertile soil:
- Soil type: Any well-drained soil; they tolerate most conditions
- Add organic matter: Dig in well-rotted compost or manure several weeks before sowing
- Avoid fresh manure: Don't add fresh manure immediately before sowing
- pH level: Slightly acidic to neutral (pH 6.0-7.0)
- Rake fine: Create a fine, level seedbed free from large clods
How to Sow Spring Onions
Spring onions are best sown directly where they'll grow:
- Create drills: Make shallow drills 1cm (½ inch) deep, 10-15cm (4-6 inches) apart
- Sow thinly: Sprinkle seeds thinly along the drill, aiming for 1cm spacing
- Cover lightly: Cover with fine soil and firm gently
- Water well: Water gently but thoroughly
- Germination: Seeds germinate in 7-14 days
Alternative: Multi-sowing in modules
- Sow 5-6 seeds per module for early crops
- Don't thin - plant out the entire clump
- Space clumps 10cm (4 inches) apart
- Harvest individual onions from each clump as needed
💡 Top Tip
Spring onions make excellent companion plants and gap-fillers. Sow them between slower-growing crops like brassicas or in spaces that will be needed later in the season.
Thinning Seedlings
Thinning isn't always necessary for spring onions:
- Spring onions can be grown quite close together
- Thin to 2-3cm (1 inch) apart if very crowded
- Use thinnings in salads - they're perfectly edible
- For larger bulbs, thin to 5cm (2 inches) apart
Ongoing Care
Spring onions are very low-maintenance:
- Watering: Water regularly during dry spells to keep soil evenly moist
- Weeding: Keep weed-free, especially when young; hand-weed carefully to avoid damaging shallow roots
- Feeding: Generally no feeding needed; avoid high-nitrogen fertilisers
- Protection: Cover autumn sowings with cloches or fleece for winter protection
Common Problems
Onion fly: Larvae tunnel into bulbs causing yellowing and wilting. Cover with fine mesh or fleece immediately after sowing.
Downy mildew: Grey-purple fuzzy growth on leaves. Ensure good spacing and air circulation; remove affected plants.
Bolting: Plants run to seed prematurely. Use bolt-resistant varieties and ensure consistent watering.
White rot: Fungal disease causing yellowing and rotting. No cure; practice crop rotation and don't grow onions in affected soil for 8 years.
Harvesting Spring Onions
Spring onions are ready to harvest quickly:
- Timing: Ready 8-12 weeks after sowing, depending on variety and season
- Size: Harvest when stems are pencil-thick (about 1cm diameter)
- Pull gently: Grasp close to the base and pull straight up, or use a hand fork to loosen soil first
- Harvest as needed: Pull individual onions as required, leaving others to grow
- Don't leave too long: Harvest before bulbs start to swell significantly
- Morning harvest: Pick in the morning when they're crispest
Storage
Spring onions are best eaten fresh but can be stored briefly:
- Fresh is best: Use within 2-3 days of harvesting for best flavour
- Refrigerator: Stand roots in a jar of water in the fridge for up to 1 week
- Plastic bags: Store unwashed in plastic bags in the fridge for up to 1 week
- Freezing: Chop and freeze in bags or ice cube trays for up to 6 months
- Regrow: Place roots in water on a windowsill to regrow green tops
Recommended Varieties
Summer Varieties:
- White Lisbon: Classic variety, quick-growing, mild flavour
- Guardsman: Uniform, upright growth, good disease resistance
- Ishikura: Japanese variety, long white stems, no bulbing
- Red Beard: Attractive red-purple stems, mild flavour
Winter-Hardy Varieties:
- White Lisbon Winter Hardy: Hardy selection for autumn sowing
- Performer: Very hardy, overwinters well, early spring harvest
- Winter White Bunching: Extremely hardy, sow August-September
Essential Tools for Growing Spring Onions
Get the right tools for successful spring onion growing:
Quick tips for growing perfect spring onions at home in the UK — from sowing in succession to harvesting crisp, mild salad onions all season long.
🧅 Did you know? Spring onions can be regrown from their roots — simply place the white root end in a glass of water on a sunny windowsill and the green tops will regrow within days.
Another angle on growing spring onions at home — great for beginners looking for a fast, rewarding crop that fits into any UK garden or container.
🌱 Quick fact: Spring onions are one of the fastest vegetables you can grow — from seed to harvest in as little as 8 weeks, making them perfect for succession sowing all season.
Vegetable Planting Calendar
See the full Vegetable Planting Calendar UK to learn the best months to plant this vegetable.
Plan Your Vegetable Garden
Get our comprehensive UK Vegetable Planting Calendar to plan your entire growing season, including when to sow and harvest spring onions alongside all your other crops.
View Planting Calendar →How To Grow Spring Onions In The UK
To grow spring onions in the UK, sow thinly in drills or containers from spring onwards, keep seedlings watered, and harvest young stems as soon as they are large enough to use. Spring onions fit well between slower crops because they take little space and can be sown in repeat batches.
This video supports the page with a practical look at sowing and growing spring onions at home, especially for small spaces and repeat sowings.
Use the UK vegetable planting calendar to plan repeat sowings. Use the UK Vegetable Garden Planner PDF to track small-space sowings, harvests, and follow-on crops.
Tools That Help With This Crop
Use these links when the guide moves from reading into sowing, planting, watering, and keeping the crop healthy.
Plan the next step
Use the printable UK Vegetable Garden Planner to turn this guide into sowing dates, bed layouts, and weekly garden tasks.