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How to Grow Cardamoms UK | Regional Planting Calendar
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RHS: pot on / start new divisions in spring under glass. Grown strictly as a conservatory/greenhouse or houseplant subject across the whole of the UK (H1B, 10-15C minimum) -- the growing regime does not vary meaningfully by UK region since it never goes outdoors year-round.
Midlands - detail & sources
Same under-glass regime as elsewhere in the UK -- RHS H1B rating means this crop is never grown outdoors year-round regardless of region.
Northern England - detail & sources
Same under-glass regime as elsewhere in the UK -- RHS H1B rating means this crop is never grown outdoors year-round regardless of region.
Scotland - detail & sources
Same under-glass regime as elsewhere in the UK -- RHS H1B rating means this crop is never grown outdoors year-round regardless of region.
Evergreen rhizomatous perennial. RHS rates it H1B, needing 10-15C minimum -- essentially a UK conservatory/greenhouse or houseplant subject, not a hardy outdoor crop. NC State gives USDA zones 10a-13b and notes temperatures below 10C (50F) cause damage.
RHS: sow fresh seed with heat, or divide fleshy rhizomes; pot into loam-based, peat-free compost with added leaf mould or granulated bark. NC State: for indoor growing, use a pot at least 10in deep with good drainage, sandy-loamy soil amended with organic matter and well-rotted manure.
Vegetative growth under glass
3
RHS: keep in bright, filtered light, sheltered, with high humidity; pot on in spring as growth resumes. NC State: light should stay dappled to deep shade, avoiding direct sun; a pebble tray with regular misting keeps humidity up for indoor plants.
Flowering (tropical conditions only)
6
RHS: white, orchid-like flowers with purple, yellow or pink markings form on shoots spreading from the base in summer -- but only reliably under genuinely tropical conditions; UK conservatory/greenhouse plants mostly stay foliage-only. NC State agrees: flowers and fruit form only under tropical conditions, not from indoor or greenhouse growing alone.
Pod set and harvest
8
NC State: small pale green/yellow-green pods, 3/4in long, holding 15-20 aromatic seeds, develop after flowering and are hand-picked just before full ripeness to prevent splitting. RHS: remove flowered stems during spring pruning to keep the clump tidy for the next season.
When to pick: NC State: 3/4in yellow-green capsules holding 15-20 aromatic seeds; hand-pick just before full ripeness to stop pods splitting and losing flavour.
Storage
Used whole or ground in curry powders, meat preservation, and beverages (NC State).
Named only vaguely by RHS ("plant viruses"), no species identified -- generic entry created rather than guessing a pathogen. NC State reports no known difficult disease problems.
RHS: generally pest-free, but susceptible to thrips under glass. NC State reports no known difficult pest problems in warm-climate outdoor growing -- read as a genuine difference in growing context (greenhouse…
RHS describes the flowers as white and orchid-like with purple, yellow or pink markings -- this close-up shows the deep purple veining on the lip that both sources note as distinctive.
Cardamom grows as a clumping, rhizomatous perennial with long, narrow, dark green leaves -- RHS gives a mature height and spread of 1.5-2.5m under glass.
NC State describes rapid growth and a rhizome-driven spread -- outdoors in the tropics plants can reach 6-15ft, though UK conservatory specimens stay considerably smaller.
NC State gives the native range as India, Burma and Sri Lanka, where cardamom grows under the shade of tall trees in hot, humid, consistently moist conditions.
NC State: the pale green to yellow-green pods that follow flowering hold 15-20 aromatic seeds each, and are hand-picked just before full ripeness to stop them splitting.
A macro view of the flower structure -- this level of detail is only really seen when cardamom is grown under genuinely tropical conditions, since RHS notes UK conservatory plants often stay foliage-only.
Light: dappled sunlight to deep shade; avoid direct sun. Soil: loamy/sandy-loamy, pH 5.5-6.8, well-drained but consistently moist, tolerates occasional flooding/wet soil. Size: 6-15ft height, 4-10ft width outdoors, rapid growth rate; indoor plants reach ~10ft in 5-10 years. Hardiness: USDA zones 10a-13b; temperatures below 50F (10C) cause damage. Native range: India, Burma, Sri Lanka. Propagation: division of fleshy, knobby rhizomes. Pests/diseases: no known difficult disease or insect problems. Harvest: 3/4in yellow-green capsules with 15-20 aromatic seeds, hand-picked before ripeness to prevent splitting; used in curry powder, meat preservation, and beverages. Indoor growing: pot at least 10in deep with drainage, sandy-loamy soil amended with organic matter and well-rotted manure, humidity tray of pebbles, regular misting.
Hardiness H1B (10-15C minimum). Soil: loam-based, peat-free potting compost with added leaf mould or granulated bark, moist but well-drained. Light: partial shade, bright filtered light, high humidity. Exposure: sheltered. Size: 1.5-2.5m height and spread, 5-10 years to maturity. Propagation: seed sown with heat when fresh, or division of rhizomes. Pests: generally pest-free, susceptible to thrips. Diseases: generally disease-free, may contract plant viruses. Care: requires tropical conditions to produce fruit; maintain high humidity; pot on in spring; remove flowered stems during spring pruning; good foliage plant under glass. Harvest: small, aromatic pale green seed capsules following white, orchid-like flowers with purple, yellow or pink markings.
2 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.
Frequently Asked Questions
When should I sow cardamoms in the UK?
In Southern England, from early March. In Scotland, wait until early March. Treat these as a guide rather than a fixed date — the governing rule is to sow only once frost risk has passed and temperatures are reliably warm enough.
When do I sow cardamoms?
Sow early March to late April.
What problems affect cardamoms?
Our data links 1 disease and 1 pest to this crop. See the sections above for each one and how to manage it.
Plan next season before the problems start
Most of the advice on this page comes down to timing and spacing — sowing at the right moment, rotating beds, and giving plants enough airflow. The UK Garden Planner lays your plot out month by month so those decisions are already made before the season starts.
UK vegetable growing guides · Checked against RHS & Met Office guidance
Every SoilCommander guide is written and maintained by our editorial team for real UK growing conditions, and reviewed against Royal Horticultural Society growing advice and Met Office climate data before publication.
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