How to Grow Kale from Seed: A Beginner's Guide
You can grow kale (Brassica oleracea Acephala Group) by sowing seed 1 cm deep in modules from March to July, then planting young plants out 45 to 60 cm apart after 5 to 6 weeks. Kale is one of the hardiest vegetables for Ireland and the UK and can be picked leaf by leaf from late summer right through winter to the following spring.
Short on time? Skip the yearly sowing. Our perennial kale Taunton Deane crops for five years or more from one plant and rarely runs to seed.
Kale (Brassica oleracea) is one of the most forgiving and nutrient-dense vegetables you can grow, shrugging off frost, poor soil, and Irish weather better than almost any other leafy green. Whether you want curly kale for hearty winter soups or tender cavolo nero for salads, it's an easy, productive crop for beginners and experienced growers alike.
This guide will walk you through how to sow kale seeds, care for seedlings, and keep plants productive through autumn and winter.
Kale Quick Facts
Latin name: Brassica oleracea Acephala Group
Sow: March to July, indoors or in a cold frame; outdoors from April
Sowing depth: 1 cm
Germination: 7 to 14 days at 10 to 20°C
Plant out: 5 to 6 weeks after sowing
Spacing: 45 to 60 cm apart
Soil: firm, fertile, pH 6.5 to 7.5
Harvest: late summer to spring
Main problems: pigeons, cabbage white caterpillars, slugs, clubroot
Step 1: Choose Your Kale Variety
Kale comes in several types, each suited to slightly different uses and growing conditions.
Curly kale: The classic frilly-leaved variety, hardy and reliable, great for soups and stews.
Cavolo nero (Tuscan kale): Dark, blistered leaves with a milder flavour, excellent in salads and pasta dishes.
Red Russian kale: Tender, flat, purple-tinged leaves that are sweeter and good raw.
Step 2: Sow Kale Seeds
Kale can be sown directly outdoors or started in trays for transplanting, and timing depends on when you want to harvest.
Sow seeds indoors or in a cold frame from March to July, or direct outdoors from April onwards once soil has warmed.
Sow seeds about 1 cm deep in trays or modules filled with peat-free seed compost, or in shallow drills if sowing direct.
Water gently and keep consistently moist; kale germinates readily at 10 to 20°C within 7 to 14 days.
Step 3: Care for Seedlings
Once seedlings emerge, a little attention early on sets them up for strong growth.
Thin direct-sown seedlings to around 45 cm apart once they have a couple of true leaves, giving plants room to bulk up.
If growing in trays, transplant seedlings once they have 4 to 5 true leaves and are large enough to handle.
Protect young seedlings from slugs, one of kale's biggest early threats, by checking plants after rain and using beer traps or wool pellets.
Step 4: Plant Out
Kale is a heavy feeder, so soil preparation matters as much as the transplanting itself.
Choose a sunny to partially shaded spot with fertile, well-draining soil enriched with well-rotted organic compost or manure.
Space plants 45 to 60 cm apart to allow for their eventual size and good airflow, which helps prevent fungal issues.
Water in well after transplanting and firm the soil around the base to help roots establish quickly.
Step 5: Ongoing Care
Watering: Keep soil evenly moist, especially during dry spells, though established kale is fairly drought-tolerant.
Feeding: Apply an organic liquid feed or top-dress with compost every few weeks during active growth for the biggest, most tender leaves.
Pest control: Cover plants with fine mesh or netting against cabbage white butterflies, whose caterpillars can strip leaves quickly, and against pigeons, which can be a serious problem in winter; companion planting with aromatic herbs like thyme can help deter pests naturally.
Cold tolerance: Kale's flavour actually improves after a frost, as cold triggers the plant to convert starches into sugars.
Step 6: Harvest Kale
Kale is a cut-and-come-again crop, meaning you can harvest for months from a single sowing.
Pick outer leaves first, starting from the bottom of the plant, leaving the central growing point intact to keep producing new leaves.
Harvest little and often for the most tender leaves, or let plants grow larger for heartier winter harvests.
With good care, kale can keep producing right through winter and into early spring, filling the "hungry gap" when little else is ready to harvest.
FAQ: Growing Kale from Seed
When should I sow kale in Ireland?
Sow kale from March to July in modules or a cold frame, or directly outdoors from April. Sowings from May to July give the best plants for harvesting through autumn and winter.
How long does kale take to grow?
Kale is ready to start picking about 8 to 12 weeks after sowing, and a single plant can then be harvested for many months.
Does kale survive winter in Ireland?
Yes. Kale is fully hardy and its flavour often improves after frost. It is one of the few crops that keeps producing through an Irish winter and into the hungry gap in spring.
Is there a kale that comes back every year?
Yes. Perennial kales such as Taunton Deane rarely flower and can crop for five years or more from one plant, without resowing.
Few crops offer as much reward for as little effort as kale: sow once and you can be harvesting fresh, nutrient-packed greens for the better part of a year.
Why You Might Prefer Perennial Kale
Annual kale is easy, but it runs to seed in its second spring and has to be resown every year. Perennial kale skips that cycle: one plant grows into a large, leafy bush you can pick from in every month of the year for five years or more.
At Earthling Plants we grow perennial kale Taunton Deane, a rarely flowering variety that shrugs off Irish winters and is easily grown on from cuttings. We also grow Daubenton's perennial kale, a compact, bushy perennial kale; if it is sold out when you visit, you can pre-order or ask to be notified. For another perennial brassica, try perennial cauliflower 9 Star, which gives small white heads every spring.
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