How to Grow Kale in the UK – Sowing, Care and Harvest Guide

Kale is one of the most valuable crops in a UK kitchen garden and one of the most underrated. It is genuinely frost-hardy – surviving temperatures well below freezing that would kill most other vegetables – and can be harvested fresh from October right through to March, filling the hungry gap when almost nothing else is available. It actually improves in flavour after the first frosts rather than deteriorating, and a single plant kept well will produce pickable leaves for five or six months continuously.

Modern kale varieties have moved a long way from the tough, bitter curly kale of previous generations. Cavolo nero, Red Russian and Redbor are genuinely delicious – tender enough to eat raw in salads when young, with complex earthy flavours that make supermarket kale look bland by comparison.

Best kale varieties for UK gardens

Sowing and raising transplants

1. 1
   Sow from April to JuneSow 2-3 seeds per module or thinly in a seedbed from April. Later sowings (May-June) are better for autumn and winter harvest as plants don’t become too large before the productive winter period begins.
2. 2
   Thin to one per moduleRemove weaker seedlings leaving one per module. Kale seedlings grow quickly – they’re usually ready to plant out 4-5 weeks after sowing.
3. 3
   Harden off before planting outMove modules outside for increasing periods over 7-10 days before planting out. Plants moved directly from indoors to outdoors suffer transplant shock that sets them back by weeks.

Planting out and spacing

Plant out from June to July when plants are 10-15cm tall with 4-5 true leaves. Kale needs generous spacing – 45cm between plants in rows 45cm apart for standard varieties, 60cm for taller varieties like Cavolo nero. Crowded kale produces smaller yields and has poorer airflow that encourages fungal problems.

Firm the soil around the roots very thoroughly after planting – kale has large leaves that act as a sail in wind, and loosely planted plants rock, causing root loosening and poor establishment.

Care through the season

• Water in dry spells through summer – particularly in the first 4 weeks after planting out while roots establish
• Weed regularly – kale is a slow starter and easily outcompeted by weeds in the early stages
• Earth up in autumn – mound soil around the stem base in October to provide wind stability as plants become top-heavy
• Stake taller varieties – varieties over 80cm in exposed positions benefit from a cane support to prevent wind rock

Harvesting correctly

• Always pick the lowest, oldest leaves first – work from the bottom upward, leaving the central growing point intact
• Pick regularly – frequent picking encourages new growth from the centre
• Never strip all leaves from a plant – always leave the top third of leaves to maintain photosynthesis
• Harvest after frost for best flavour – frost converts starches to sugars, significantly improving sweetness

Common problems

Kale is one of the most reliable and productive winter crops available to UK gardeners. Sow in May or June, plant out in July with good spacing and netting, and you will be picking fresh leaves through to March. For more on winter cropping read our guide on how to grow leeks in the UK.