How to Grow Spring Onions
Allium fistulosum
When to Start
Direct sow outdoors as soon as soil reaches 5°C — typically early to mid spring. Can also be started indoors 4 weeks earlier for a head start.
Don't know your frost date? Find it here →
Growth Stages
Approximate days from start
Care Essentials
- Light balanced feed at sowing. Quick-growing — rarely needs much feeding.
- Sow every 3–4 weeks for continuous supply. Quick and easy — ready in 8–12 weeks.
Companion Planting
—
Growing Conditions
Get a personalized schedule for Spring Onions based on your exact frost dates
Start planning freeEnter your last frost date to see your dates
- Sow indoors
- —
- Transplant out
- —
- First harvest
- —
Want your full season plan with reminders? Try Leaftide free
Spacing & Planting
| Plant spacing | 2 cm |
| Row spacing | 15 cm |
| Sow depth | 1 cm |
| Mature height | 30 cm |
| Mature spread | 5 cm |
Also known as Scallions or Bunching Onions. Sown thickly in a band to be harvested before they bulb up.
Care Guide
- Feeding
- Light balanced feed at sowing. Quick-growing — rarely needs much feeding.
- Watch for
-
- Onion fly
- Downy mildew
- Rust
Pests & Diseases
Pest Onion Fly
Identification: Plants wilt and yellow despite adequate water; small white maggots found at the base of stems when pulled; soft, rotting tissue
- Cover rows with fine mesh or enviromesh from sowing to prevent egg-laying
- Firm soil around plants — loose soil attracts egg-laying females
- Rotate allium crops on a 3-year cycle
- No effective chemical treatments available to home gardeners; barrier methods are the primary control
Pest Allium Leaf Miner
Identification: Lines of white dots on leaves where adult flies have punctured tissue; brown pupae visible inside leaves; distorted, twisted growth
- Cover crops with fine mesh from March to April and again September to November
- Check plants regularly and remove any with visible mines or pupae
- Rotate allium crops
- No effective chemical treatments; physical barriers are the only reliable control
Pest Onion Thrips
Identification: Silvery-white streaks and patches on leaves; tiny, slender yellow-brown insects visible on foliage; leaves may become distorted
- Spray with insecticidal soap
- Keep plants well-watered as thrips prefer dry conditions
- Encourage natural predators
- Spray with a contact insecticide containing pyrethrins
Disease Downy Mildew Peronospora destructor
Symptoms: Pale, greyish-purple fuzzy growth on leaves; leaves yellow from the tips downwards and collapse; plants may die in severe cases
Treatment: Remove affected foliage; improve air circulation; avoid overhead watering
Prevention: Space plants well; ensure good airflow; avoid wet foliage; plant in well-drained soil; rotate crops
Disease Rust Puccinia allii
Symptoms: Bright orange pustules on leaves; leaves yellow and die back prematurely; reduced plant vigour
Treatment: Remove badly affected leaves; improve air circulation
Prevention: Space plants well; avoid high-nitrogen feeds; rotate allium crops; clear debris at end of season
Disease White Rot Sclerotium cepivorum
Symptoms: Yellowing and wilting foliage; fluffy white fungal growth at the base of plants; small black sclerotia visible in the mycelium
Treatment: No cure — remove and destroy infected plants and surrounding soil; do not compost
Prevention: Never plant alliums in soil where white rot has occurred; rotate on a very long cycle (8+ years); avoid moving contaminated soil
Growing Conditions
| Min. soil temperature | 5°C |
| Germination temperature | 10–25°C |
| Base growth temperature | 5°C |
| Min. daylength to start | 8.5h |
| Photoperiod sensitivity | day neutral |
Frequently Asked Questions
- How far apart should I plant Spring Onions?
- Plant Spring Onions 2cm apart with 15cm between rows.
- When can I harvest Spring Onions?
- Spring Onions is ready to harvest approximately 45 days after transplanting.
- Is Spring Onions frost hardy?
- Spring Onions is classified as Hardy.
Plan Spring Onions in your garden — get personalized frost-date scheduling
Start planning free