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🧅🌱 Planting Onions UK | How to Grow Your Own Onions from Sets or Seed
🌿 Introduction: Why Grow Your Own Onions?
Onions are one of the easiest and most rewarding vegetables to grow in the UK. They take up little space, store well, and are used in countless recipes.
By growing your own onions, you get:
✔ fresher flavour
✔ better storage quality
✔ a wide choice of varieties
✔ great value for money
Whether you choose onion sets or seed, both methods can produce excellent results when grown correctly.
Below
⭐ Check Out Our Recommended Products
• Onion Sets (Spring or Autumn Planting)
Quick and reliable way to grow onions.
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• Onion Seeds
Wider variety choice and cheaper for larger crops.
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• Free-Draining Garden Compost
Improves soil structure and prevents rot.
Click here to see them
🧅📅 1. When to Plant Onions in the UK
Timing depends on whether you’re planting sets or seeds.
Onion sets:
✔ Spring planting: March–April
✔ Autumn planting: October–November (overwintering varieties only)
Onion seeds:
✔ Sow indoors: January–February
✔ Sow outdoors: March–April
Avoid planting into frozen or waterlogged soil.
🌱🪴 2. Growing Onions from Sets
Onion sets are small, immature bulbs and are the easiest option for beginners.
How to plant sets:
✔ choose firm, healthy sets
✔ plant with the pointed end up
✔ leave the tip just above soil level
✔ space 10–15cm apart
✔ rows 25–30cm apart
Water well after planting and keep weed-free.
🌾🌱 3. Growing Onions from Seed
Growing from seed gives more variety and often better storage onions.
How to grow from seed:
✔ sow thinly in modules or seed trays
✔ cover lightly with compost
✔ keep moist and warm
✔ transplant when pencil-thick
Thin seedlings to avoid overcrowding.
☀️🌧️ 4. Best Soil and Position for Onions
Onions thrive in:
✔ full sun
✔ free-draining soil
✔ fertile but not freshly manured ground
Heavy soil should be improved with compost or grit.
💧🌿 5. Watering and Feeding Onions
Onions don’t like extremes.
Watering:
✔ water regularly in dry spells
✔ avoid waterlogging
Feeding:
✔ apply a balanced feed in early growth
✔ stop feeding once bulbs start swelling
Too much nitrogen causes leafy growth instead of bulbs.
🚫❌ 6. Common Onion Growing Problems
Bolting (flowering early)
✔ caused by cold stress or damaged sets
✔ use bolt-resistant varieties
Onion fly
✔ cover crops with mesh
✔ rotate crops yearly
Small bulbs
✔ overcrowding
✔ poor feeding
✔ lack of sunlight
Good spacing is essential.
🌾✂️ 7. Harvesting Onions
Onions are ready when:
✔ foliage turns yellow
✔ tops fall over naturally
Lift gently and allow to dry on the soil surface or under cover for 2–3 weeks.
🏡🧅 8. Storing Onions
Correct storage extends shelf life.
Storage tips:
✔ ensure onions are fully dry
✔ store in a cool, dry, airy place
✔ hang in nets or plaits
Properly stored onions can last 6–9 months.
🌟 FAQs
Are onion sets better than seeds?
Sets are easier; seeds offer more choice and better storage.
Can I plant onions in autumn in the UK?
Yes — use overwintering varieties only.
Why are my onions going to seed?
Cold weather or stressed plants cause bolting.
Do onions need lots of water?
Moderate watering is best — avoid extremes.
How many onions do you get from one set?
One set produces one onion.