Crop type: Onions
Allium cepa ‘Marshalls Red Fen’
Common name: Onion ‘Marshalls Red Fen’
Crop slug: onions
This Allotment Pro editorial draft summarises the cited RHS cultivar profile and its linked crop guidance. Check the sources and adjust cultivation decisions for local conditions.RHS cultivar profile
1 - Overview
‘Marshalls Red Fen’ is a bulbous onion with upright blueish-green leaves and rounded dark-red bulbs of good flavour. It is planted in autumn and harvested the following June or July, giving an earlier crop than spring-planted storage onions. The RHS name status is unresolved.
It suits free-draining ground where sets can pass the winter without rotting. Avoid autumn planting in cold waterlogged soil; modules under cover provide an alternative start.
2 - Size
- Ultimate height
- 0.1–0.5 metre
- Ultimate spread
- 0.1–0.5 metre
- Time to ultimate size
- 1–2 years
Space sets 5–15cm apart in rows 20–30cm apart. Wider spacing supports larger rounded bulbs and improves airflow.
3 - Growing conditions
- Suitable soils
- Loam or sand
- Moisture
- Well drained
- Preferred pH
- Neutral or alkaline
Grow in fertile soil enriched before planting. Water in dry periods while plants are actively growing, but stop once bulbs become swollen so skins can ripen.
4 - Position and hardiness
- Light
- Full sun
- Aspect
- South- or west-facing
- Exposure
- Sheltered
- Hardiness
- H3
Choose a sunny protected site with excellent winter drainage. In harsher or wetter gardens, start sets in modules in a cool bright greenhouse and transplant in spring.
5 - Colour and seasonal interest
Upright blueish-green leaves provide winter and spring structure. Rounded bulbs develop dark-red papery skins by early summer. Remove premature flowers so energy remains in the bulb.
6 - Botanical details
- Family
- Amaryllidaceae
- Native to Great Britain and Ireland
- No
- Foliage
- Deciduous
- Habit
- Clump forming
- Name status
- Unresolved
Genus
Allium includes onion- and garlic-scented bulbous herbs with linear, strap-shaped or cylindrical leaves and umbel-borne star- or bell-shaped flowers.
Safety
The bulbs are edible. Use damaged bulbs promptly and cure only firm, sound specimens for storage.
7 - How to grow
Cultivation
Plant suitable sets in autumn in fertile free-draining soil in full sun, about 2cm deep with their tips just visible. Protect them from birds until rooted. Keep weed-free and water during dry spells, stopping after bulbs swell.
Harvest in June or July when foliage yellows and falls naturally. Lift carefully and cure for about two weeks before storing. Autumn onions generally store for less time than spring crops, so use them by early winter.
Propagation
Propagate by seed or onion sets.
Suggested locations
- City or courtyard garden
- Cottage garden
- Patio container
- Flower border or bed
- Sunny vegetable plot
Pruning
Remove faded leaves and spent flowers. Take out flower stalks immediately during bulb production.
Pests
May be susceptible to stem and bulb eelworm, leek moth and onion fly.
Diseases
May be susceptible to rusts. Rotation, drainage and good airflow reduce disease pressure.