How to Grow Cardoons UK | Regional Planting Calendar

Regional Planting Calendar

Region	Sow
Southern England	early March to mid April
Midlands	early March to mid April
Northern England	early March to mid April
Scotland	early March to mid April

Southern England - detail & sources

Johnny's Selected Seeds: start seed indoors 6-8 weeks before transplanting in spring; a single window is applied uniformly across all four sub-regions since the source gives no UK-region-specific gradient, and plants are typically raised under cover before planting out regardless of region.

Midlands - detail & sources

Johnny's Selected Seeds: start seed indoors 6-8 weeks before transplanting in spring; a single window is applied uniformly across all four sub-regions since the source gives no UK-region-specific gradient, and plants are typically raised under cover before planting out regardless of region.

Northern England - detail & sources

Johnny's Selected Seeds: start seed indoors 6-8 weeks before transplanting in spring; a single window is applied uniformly across all four sub-regions since the source gives no UK-region-specific gradient, and plants are typically raised under cover before planting out regardless of region.

Scotland - detail & sources

Johnny's Selected Seeds: start seed indoors 6-8 weeks before transplanting in spring; a single window is applied uniformly across all four sub-regions since the source gives no UK-region-specific gradient, and plants are typically raised under cover before planting out regardless of region.

Quick Facts

Factor	Value
Soil pH	5.5 - 7
Sunlight	6-6 hours direct sun
Optimal growing temp	14-28C
Minimum survivable temp	-10C
Drainage	Well-drained
Lifecycle	perennial
Edible parts	leaf stalks (petioles)

At a Glance

Soil & Growing Conditions

Soil pH range

5.5 7

Span reflects genuine variation between the cited authorities, not a single agreed figure.

Growth Stages

Stage	BBCH	Notes
Sowing and raising young plants	0	Start seed indoors 6-8 weeks before transplanting, 2-3 seeds 1/4in deep per cell, germinating at 70-80F (Johnny's Selected Seeds).
Transplanting and establishment	1	Transplant 2-3ft apart in rows 3-6ft apart, in full sun, sheltered from strong wind, in well-drained fertile soil (Johnny's Selected Seeds, RHS).
Leafy growth and blanching	4	For the mildest flavour, blanch the leaf stalks for the last 4-6 weeks before harvest by tying the leaves and wrapping the stems in paper, cloth or similar to exclude light; check frequently, as plants are more prone to rotting while blanched (Johnny's Selected Seeds).
Harvest	8	Ready to harvest 4-6 weeks after blanching begins; cut stalks off at ground level and trim away the leaves (Johnny's Selected Seeds).

Harvest & Storage

When to pick: NC State: "The young, emerging leaf stalks are blanched, harvested, cooked, and eaten as a vegetable." RHS: cut down flower stems as they emerge in summer if growing it as a foliage/blanching plant rather than for flowers.

Storage

Best used fresh soon after blanching and harvest

Diseases

Grey mould

Botrytis cinerea

Soft brown fruit decay; Fuzzy grey-brown mould

Powdery mildew

Pests

Aphids

Aphididae (various spp.)

Slugs

Gastropoda (slugs, various spp.)

Snails

Gastropoda (snails, various spp.)

Cardoon, Grown for Its Blanched Leaf Stalks

Silvery-grey, deeply divided leaves

RHS: silvery-grey, divided, spiny leaves up to a metre long -- the distinctive feature that sets cardoon apart from its close relative, globe artichoke.

A robust Mediterranean perennial

RHS: a robust, clump-forming herbaceous perennial reaching up to 2.5 metres, native to the Mediterranean.

Grown for stalks, not buds

Unlike globe artichoke, cardoon is grown for its thick, fleshy leaf stalks rather than its flower buds.

Large thistle-like flowers

RHS: large, thistle-like purple flowers appear in late summer and autumn if the plant is left unharvested.

Blanched for the mildest flavour

Leaf stalks are blanched for four to six weeks before harvest by excluding light, softening their flavour.

References

1. FAO EcoCrop - Cynara cardunculus data sheet

   country=INTL

2. GBIF - GBIF Backbone Taxonomy: Cynara cardunculus

   country=INTL

3. NC State Extension Gardener Plant Toolbox - Cynara cardunculus (Artichoke Thistle, Cardoon, Scottish Thistle, Wild Artichoke)

   country=USA

4. RHS - Cynara cardunculus | cardoon

   country=UK

5. Royal Horticultural Society - Grey mould: Symptoms, Causes & Control

   country=UK

6. Royal Horticultural Society - Powdery mildews

   country=UK

7. Royal Horticultural Society (RHS Advice Team) - Aphids: Identification and Control

   Directly fetched and verified. RHS explicitly does not recommend pesticide use against aphids; recommends tolerance, manual squashing, and encouraging/purchasing natural predators (ladybirds, hoverflies, lacewings, parasitoid wasps, earwigs) as biological control, especially under glass.

8. Royal Horticultural Society (RHS Advice Team) - Slugs and Snails

   Directly fetched and verified (canonical URL differs from requested URL /biodiversity/slugs -> redirects to /biodiversity/slugs-and-snails). RHS explicitly advises against slug pellets (even organic) due to wildlife harm, and cites RHS's own controlled trial finding no damage reduction from physical barriers (copper tape, bark mulch, eggshell, grit, wool) -- while also noting some other studies have shown copper barriers to repel slugs, a preserved disagreement rather than a silently resolved one. Details Nemaslug (Phasmarhabditis hermaphrodita) biological control including application temperature range and its lack of effect on snails specifically.

8 independent sources are cited for this crop. Where they disagree - soil pH is the clearest case - every figure is preserved rather than averaged into false precision.