Onion setsSmall immature bulbs planted directly rather than grown from seed, giving a faster, more reliable crop in a short growing season. Full definition → do well in Scotland, and the main choice is when to plant them. Of the six varieties the RHS recommends, two can go in during autumn for an early crop, and the rest are planted in spring and store for longer.
Quick answer
Sturon for most gardens, since it can be planted in autumn or spring. Marshalls Red Fen for a red onion from an autumn set, and Red Baron for a red one from spring. Hercules for large bulbs and Rumba for storage, both planted in spring.
What Scotland means for the choice
Cold weather in spring is what makes onions bolt, and spring comes later in much of Scotland (see the frost dates). OverwinteringKeeping a plant alive and intact through the cold months, whether left outdoors, moved under cover, or stored dormant. Full definition → sets planted in autumn are less sensitive to that cold, and heat-treated sets greatly reduce the risk from a spring planting. But autumn sets sit in wet ground all winter, and on heavy soil that waterlogs they're likely to rot, a real risk in Scotland's wetter climate. On that kind of soil, plant in spring. All six share the same hardiness ratingThe RHS's H1a–H7 scale for how much cold a plant can survive outdoors, H1a being tender indoor-only and H7 hardy anywhere in the UK. Full definition →, so it doesn't separate them. The onion growing guide covers planting, spacing, feeding and storage.
| Variety | Plant sets | Colour | Known for |
|---|---|---|---|
| Sturon | March–April or autumn | Straw-coloured | Reliable, excellent flavour, stores well |
| Marshalls Red Fen | Autumn | Dark red | Good flavour, stores well, ready June–July |
| Hercules | Spring | Dark golden-brown | Large bulbs, strong flavour, good resistance to boltingA plant switching early into flowering and seed production, usually triggered by stress, after which leaves, roots or bulbs turn bitter or unusable. Full page → |
| Rumba | Spring | Yellow-brown | Vigour and storage, ready from August |
| Centurion | No time given | Golden-brown | Early cropping, crisp flesh, stores well |
| Red Baron | No time given | Dark red | Mid to late summer, strong flavour, stores well |
All except Marshalls Red Fen hold the RHS Award of Garden Merit (AGMThe RHS's Award of Garden Merit: a UK-wide trials award for reliable performance, not a Scotland-specific recommendation. Full definition →).
Autumn sets: Sturon and Marshalls Red Fen
Sturon is the only one of the six listed for both seasons: plant sets in March or April for a late summer harvest, or in autumn for a crop the following summer. It's popular and reliable, with excellent flavour, and it stores well. It prefers a sheltered site.Marshalls Red Fen, without the AGM, is a red onion with good flavour, planted in autumn and lifted in June or July. Autumn-planted onions give the earliest crop, but they only store until early winter.
Spring sets: Hercules and Rumba
Hercules produces large, almost round bulbs with a strong flavour and dark golden-brown skin, and it has good resistance to bolting, which helps after a cold spring.Rumba is British-bred, with better vigour, shape and storage than Sturon, giving medium-sized, yellow-brown bulbs from August. Hercules and Rumba are both listed for spring planting only. Spring-planted onions are ready from July to October and can last well into the following spring.
Centurion and Red Baron
Neither listing gives a planting time. Most sets are planted in early to mid-spring, and autumn sets are sold as overwintering types, so plant these two in spring unless the supplier says otherwise. Centurion is an early cropper with golden-brown skin and crisp, creamy-white flesh. Red Baron crops in mid to late summer, with dark red skin and white flesh ringed in red, and has a strong flavour.
Which one for your situation
- Most gardens: Sturon.
- A red onion from an autumn set: Marshalls Red Fen.
- A red onion from a spring set: Red Baron.
- Large bulbs: Hercules.
- Onions to store into spring: Rumba, planted in spring.
- Heavy soil that sits wet in winter: any except Marshalls Red Fen, planted in spring.
Watch for white rot and downy mildew, which are worse in damp conditions, and see bolting if plants run to flower.
Common questions
Can I plant Hercules or Rumba sets in autumn?
Both are listed for spring planting only. For an autumn set, choose Sturon or Marshalls Red Fen.
Why do my onions keep bolting?
Cold weather in spring is the usual cause. Overwintering sets planted in autumn are less sensitive to it, heat-treated sets greatly reduce the risk from a spring planting, and Hercules has good resistance to bolting.
Do autumn-planted onions store well?
Only until early winter. Spring-planted onions can last well into the following spring, so plant in spring if you want onions to keep.
Sources
Show the 7 sources
- Onions: how to grow: The six recommended varieties and AGM status; bolting from spring cold; overwintering and heat-treated sets; avoid autumn planting on waterlogged soil; harvest and storage times
- Allium cepa (Cepa Group) 'Sturon': Traditional, reliable, straw-coloured bulbs; March-April or autumn planting; sheltered site
- Allium cepa 'Marshalls Red Fen': Dark red bulbs planted in autumn, harvested June to July
- Allium cepa 'Hercules': Large, almost round bulbs with dark golden-brown skin; spring planting
- Allium cepa 'Rumba': British-bred; better vigour, shape and storage than Sturon; yellow-brown bulbs from August; spring planting
- Allium cepa (Cepa Group) 'Centurion': Golden-brown skin, crisp creamy-white flesh; no planting time given
- Allium cepa (Cepa Group) 'Red Baron': Dark red skin, red-rimmed white flesh, strong flavour; no planting time given