Onion Sets for Northern Irish Gardens – Grow in Spring or Autumn

When to Sow Onion Sets in Northern Ireland

In Northern Ireland, spring onion sets like Sturon, Snowball, and Red Karmen can be planted from early March to mid-April. For overwintering onion sets such as Troy F1 and Senshyu Yellow, plant from mid-September to late October.

Northern Ireland’s temperate, maritime climate makes it possible to grow onions in both spring and autumn, though well-drained soil is essential due to higher rainfall.

Best Time to Plant Onion Sets in Northern Ireland

• Spring sets: Plant from early to mid-March through April
• Autumn sets: Mid-September to late October

Ensure the ground isn’t waterlogged before planting. Use fleece or mesh tunnels in more exposed areas to offer protection from wind and heavy rain.

How to Grow Onion Sets in Northern Ireland

• Choose a sunny site with free-draining soil or raised beds
• Push sets in with tips just above the surface, spaced 10cm apart
• Weed regularly and protect young shoots from birds
• Mulch lightly to reduce soil compaction and retain moisture
• Avoid high-nitrogen feeds to prevent excessive top growth

Can You Grow Onion Sets in Northern Ireland?

Yes! Onion sets grow well across Northern Ireland. Spring planting is reliable in most areas, and autumn planting works well when done early enough to establish before the first frosts. Raised beds or mounded rows help keep bulbs from sitting in wet soil.

Tips for Growing Onion Sets in Northern Ireland

• Improve drainage by adding compost or grit to heavy soils
• Use cold-hardy varieties for overwintering success
• Plant in well-spaced rows to reduce risk of rot or mildew
• Rotate crops yearly to avoid disease build-up
• Harvest onions when the tops begin to fall and dry naturally

Best Onion Set Varieties for Northern Ireland

• Troy F1 – Cold-hardy overwintering variety, fast and reliable
• Senshyu Yellow – Excellent flavour and great frost resistance
• Sturon – Spring-planted classic with strong growth and storage
• Red Karmen – Mild red variety perfect for salads
• Snowball – Early white onion, ideal for well-drained sites
• Red Winter – A tough red overwintering variety for early harvest

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