Crop type: Calabrese
Brassica oleracea (Italica Group) ‘Marathon’
Common name: Calabrese ‘Marathon’
Crop slug: calabrese
This Allotment Pro editorial draft summarises the cited RHS cultivar profile. Check the source and adjust cultivation decisions for local conditions.RHS cultivar profile
1 - Overview
‘Marathon’ is a hardy biennial grown as an annual summer vegetable. It is exceptionally reliable and carries medium-sized, dense heads with a notably good flavour over a long harvest period. The parent crop guide describes the heads more specifically as firm and blue-green.
The profile records that ‘Marathon’ grows in most soil textures and has some disease resistance. Its long season and dependable head production make it suitable for growers who want repeated useful harvests rather than a brief flush.
2 - Size
- Ultimate height
- 0.5–1 metre
- Ultimate spread
- 0.1–0.5 metres
- Time to ultimate size
- 1 year
‘Marathon’ can grow taller than the other recommended calabrese cultivars, so allow for its height and support plants on exposed plots. It completes its productive life cycle within the first growing season.
3 - Growing conditions
- Suitable soils
- Sand, loam, chalk and clay
- Moisture
- Well-drained or moist but well-drained
- Soil pH
- Neutral or alkaline
This adaptable cultivar accepts all four common soil textures when drainage is sound. Prepare fertile, firm ground and maintain adequate moisture for steady head development without leaving the roots waterlogged.
4 - Position and hardiness
- Light
- Full sun
- Aspect
- West- or south-facing
- Exposure
- Sheltered
- Hardiness
- H2 — tolerant of cool conditions but not freezing, fitting its treatment as a summer annual crop
Choose a sunny and sheltered site. Because plants can reach up to 1 metre tall, secure rooting in well-compacted soil and shelter from buffeting winds are particularly useful as the dense heads mature.
5 - Colour and seasonal interest
The profile’s seasonal table contains no assigned flower, foliage or fruit colours. The parent guide identifies the long-season edible heads as firm and blue-green, while the live profile describes them as dense and medium-sized.
6 - Botanical details
- Family
- Brassicaceae
- Native to Great Britain and Ireland
- No
- Foliage
- Deciduous
- Habit
- Clump-forming
- Name status
- Accepted
Genus
Brassica contains annual, biennial and perennial plants, commonly upright with alternate and often glaucous leaves, long taproots and clusters of cross-shaped yellow or white flowers. The genus includes many familiar food crops, among them cabbages, turnips, mustards and oilseed rape.
7 - How to grow
Cultivation
Grow ‘Marathon’ in fertile, firmly compacted, non-acid soil in full sun. Sow in spring in shallow drills at 1.5cm deep. When seedlings reach 10–15cm tall, thin or transplant them to 45cm apart. Keep growth steady and harvest the dense heads while their buds remain tightly closed.
Propagation
Propagate by seed, either sown as a vegetable crop outdoors or started indoors before careful transplanting.
Pruning
No pruning is required. Cut only the edible heads as they reach harvest stage and remove badly damaged leaves when necessary.
Pests
Possible pests include birds, cabbage caterpillar, cabbage whitefly, cabbage root fly, cutworms, flea beetle, mealy cabbage aphid, slugs and snails. A close-fitting fine mesh barrier protects the developing crop against several of these threats.
Diseases
The profile lists black rot, club root, downy mildew, grey mould, leaf spot and white blister as possible diseases, while noting some general disease resistance in the cultivar description. Rotation, neutral or alkaline well-drained soil, clean plants and adequate spacing reduce disease pressure.