Plant
- Late winter–mid-springPlant firm tubers outdoors once the site can be prepared.
- Late winter–early springStart tubers in outdoor pots if the ground is frozen, saturated or not yet ready, then transplant in late spring.
Jerusalem artichokes
This Allotment Pro editorial draft summarises the cited RHS guide. Check the source and adjust timings for local conditions.RHS source guide
Month by month
Harvest
- Late autumn–winterLift tubers as required, leaving the remainder protected in the ground.
- Late winter–early springFinish harvesting before vigorous new shoots establish, unless retaining plants for another crop.
1 - Getting Started
Jerusalem artichokes, *Helianthus tuberosus*, are hardy perennial sunflowers grown for edible underground tubers. They originate from North America rather than Jerusalem and are often called sunchokes. The name may derive from the Italian *girasole*, meaning sunflower. They share the Asteraceae family with globe artichokes but otherwise have little in common with that crop.
Plant tubers rather than seed, much as you would potatoes. Tall leafy stems grow through summer, often reaching 3m (10ft), then tubers are ready from late autumn through winter. The plants tolerate partial shade and imperfect soil, although full sun, moisture-retentive ground and reasonable fertility give a better yield. They are vigorous and need little routine care.
A few overlooked tubers will sprout again in spring, so decide whether the bed is to be permanent. This persistence makes an annual crop easy to renew but can make unwanted plants difficult to remove. Large containers provide a controlled alternative for smaller gardens.
2 - Choosing What To Grow
Only a small range is widely available in the UK. Select firm, smooth planting tubers, ideally a little smaller than a hen's egg. Smoother cultivars are easier to clean and peel; shorter ones are more manageable on exposed plots and in containers. After the first harvest, save the best smooth tubers for replanting.
Recommended varieties
‘Dwarf Sunray’
A compact choice for exposed sites, growing about 120–150cm (4–5ft) tall and producing long, smooth, pale tubers.
‘Fuseau’
A tall cultivar reaching 2m (6½ft) or more, with large, relatively smooth, thin-skinned tubers that are easy to prepare.
3 - Preparing The Ground
Choose a sunny position with moderately fertile, moisture-retentive soil. Partial shade and poorer ground are tolerated but usually reduce the crop. Avoid land that becomes waterlogged, because saturated soil can rot the tubers.
Before planting, fork in one bucketful of well-rotted garden compost or other organic matter per square metre or square yard. In a no-dig bed, apply organic matter as a surface mulch and plant directly through it. Consider the crop's eventual height before choosing the bed: a row on the northern edge can avoid shading smaller vegetables, while several rows may form a useful windbreak.
Allow for future control as well as the first crop. Tubers can spread wide and travel deep in light soil, and even a small piece left after harvest may regrow. A contained bed or large pot is useful where persistent shoots would be unwelcome.
4 - Planting
Plant from late winter to mid-spring. Use firm, smooth tubers without rot. Large specimens can be cut in half provided every piece retains at least one visible bud.
Planting in the ground
Set tubers 10–15cm (4–6in) deep and 30cm (1ft) apart in rows or staggered rows. Leave at least 1m (3ft) between rows where access is needed. For a dense block or windbreak, rows may be as close as 30cm (1ft). Water thoroughly after planting.
Planting in containers
If outdoor soil is frozen, too wet or unprepared, start tubers in pots outdoors and transplant the young plants in late spring. For a complete container crop, choose a vessel at least 45cm (18in) wide and deep. Plant one or two tubers 10–15cm (4–6in) deep in peat-free multipurpose compost, then stand the pot in a sheltered place in sun or partial shade.
Compact cultivars are best for pots. Container plants need more frequent watering and usually crop less heavily than plants in open ground, but the pot confines persistent tubers and makes harvesting easier.
5 - Plant Care
Jerusalem artichokes are vigorous and need little attention beyond moisture, mulch and support. Their main crop forms below ground, so summer care aims to keep stems stable and foliage working until autumn.
Watering
Water during dry summer spells so the tubers swell. Drought can result in smaller, more knobbly tubers that take longer to clean and prepare. Check container compost throughout the growing season because it dries much faster than open soil.
Mulching
After planting in late winter or spring, mulch with well-rotted organic matter. This conserves moisture, suppresses weeds and supports steady growth.
Supporting
When stems reach about 30cm (1ft), draw a 15cm (6in) mound of soil around their bases. This stabilises the clump. In windy gardens, place tall canes, hazel stems or other sturdy supports around the outside and contain the growth with twine. Preventing wind-rock protects both stems and the developing tubers.
6 - Pruning And Training
On exposed plots, tall unsupported stems can be reduced to about 1.5m (5ft) in late July or August. Do not cut lower at this stage, as excessive foliage removal may reduce the tuber crop. Supporting the stems instead preserves their full leaf area.
Yellow sunflower-like blooms appear in late summer or autumn and provide food for pollinators. Leave them for display and wildlife value, or remove them so more energy goes into swelling the underground crop.
When foliage yellows in autumn, cut every stem to about 8cm (3in). The remaining stumps mark the tuber positions. Lay the cut growth over the bed to insulate the ground, making winter lifting easier during frosty weather.
7 - Harvesting And Storing
Harvest from late autumn onwards with a garden fork. A plant should generally produce at least ten tubers. Lift only what is needed, working carefully because tubers may be deep and widely spread, especially in light soil.
Tubers are very hardy and do not store well indoors, so keep them in the ground through winter. In colder regions, cover the bed with cut stems, a thick organic mulch or cardboard to prevent the soil freezing solid. Frost is said to improve flavour, and tubers do not become woody when left underground.
Remove every piece if the crop must not return. Otherwise, leave a few smooth sound tubers in place or replant selected specimens for the next season.
The crisp tubers have a nutty flavour and can be steamed, roasted or baked like potatoes. Smooth thin-skinned forms may not need peeling. Jerusalem artichokes contain a carbohydrate that is not fully broken down during digestion and may cause wind, especially in large portions. Begin with a small serving. Cooking with lemon juice or harvesting later may reduce the effect for some people.
8 - Problem Solving
The plants are generally robust and rarely sustain serious damage. Slugs and snails may nibble emerging shoots and can feed on tubers over winter, while older top growth usually tolerates minor grazing. Avoid waterlogged soil, remove diseased material and keep the bed accessible for inspection.
Common problems
Sclerotinia disease
This soil-borne fungal disease can affect stems and other tissues and persists in the ground for long periods. Remove infected plants promptly, avoid moving contaminated soil and rotate susceptible crops away from the site.
Problem sourceSlugs and snails
These molluscs feed on young shoots and may tunnel into winter tubers. Encourage natural predators, remove hiding places near vulnerable growth and inspect beneath mulch when damage becomes significant.
Problem source