Crop type: Kohlrabi
Brassica oleracea (Gongylodes Group) ‘Olivia’ AGM
Common name: Kohlrabi ‘Olivia’ AGM
Crop slug: kohl-rabi
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
‘Olivia’ is a hardy biennial grown as an annual vegetable. It is a high-quality green-skinned cultivar with a small, globe-shaped, light-green edible swollen stem and upright dark-green leaves. It is slow to bolt and has excellent tolerance of mildew and other fungal diseases.
Its compact light-green globe and strongly upright, darker foliage give it a recognisable harvest-stage silhouette. Sow every three weeks or so to use its suitability for successional cropping. The RHS profile displays an Award of Garden Merit, while listing the botanical name status as unresolved.
2 - Size
- Ultimate height
- 0.1–0.5 metre
- Ultimate spread
- 0.1–0.5 metre
- Time to ultimate size
- 1 year
This compact clump suits close vegetable spacing, raised beds and large containers. Its edible globe remains characteristically smaller than that of large kohlrabi cultivars.
3 - Growing conditions
- Suitable soils
- Loam, sand or chalk
- Moisture
- Well-drained
- Soil pH
- Neutral or alkaline
Grow in light, free-draining, non-acid soil. Add mature organic matter before sowing and maintain even moisture so each small globe swells steadily without becoming tough.
4 - Position and hardiness
- Light
- Full sun
- Aspect
- South- or west-facing
- Exposure
- Sheltered
- Hardiness
- H3 — hardy in coastal and relatively mild parts of the UK
Use a warm, sunny and sheltered position. Although slow bolting is a useful trait, protect early seedlings from prolonged cold and other checks that could interrupt growth.
5 - Colour and seasonal interest
The small swollen stem is globe shaped and light green, with green skin and edible flesh. Upright dark-green leaves rise clearly above it, making the foliage more vertical than a sprawling brassica rosette. Green colour is present through spring, summer and autumn; flowers are not expected on a normally harvested annual crop.
6 - Botanical details
- Family
- Brassicaceae
- Native to Great Britain and Ireland
- No
- Foliage
- Deciduous
- Habit
- Clump forming
- Name status
- Unresolved
Genus
Brassicas may be annual, biennial or perennial. Most are upright with alternate, often glaucous leaves, long taproots and clusters of cross-shaped yellow or white flowers. The genus includes many familiar food crops.
Safety
No specific handling warning is listed on the exact RHS profile. Wash the swollen stem and foliage thoroughly and peel any tough outer skin before eating.
7 - How to grow
Cultivation
Sow directly from March to July, about 1.5cm deep in drills 30cm apart, then thin seedlings to 15cm between plants. Green varieties can be sown early. Alternatively, start seed indoors and transplant outside in May or June.
For a continuing harvest, sow another small batch about every three weeks. Keep the soil evenly moist and weed-free while the light-green globes swell. Slow bolting and strong fungal tolerance add resilience, but sound rotation and airflow remain important.
Propagation
Propagate by seed. Successional sowing is especially appropriate for this cultivar.
Suggested locations
- Sunny vegetable plot
- Raised bed
- Large patio container
- Successional cropping row
Pruning
No pruning is required. Remove damaged leaves only and harvest the whole swollen stem when young and tender.
Pests
May be susceptible to birds, cabbage caterpillars, cabbage whitefly, cabbage root fly, cutworms, flea beetles, slugs and snails.
Diseases
May be susceptible to black rot, club root and leaf spot. ‘Olivia’ is noted for excellent tolerance of mildew and other fungal diseases, but this does not replace crop rotation, drainage and airflow.