Growing Kale in Scotland: The Complete Guide

Brassica oleracea (Acephala Group)

Everything you need to grow kale in Scotland, a crop that stands through the winter and crops when almost nothing else will. We have done the research so you don't have to.

Most pages on this site have to explain what Scotland takes away from a crop. Not this one. Kale is hardy, forgiving, and it crops through the hungry gap when the garden is otherwise bare. It is also a crop our climate genuinely favours. If you grow one thing over a Scottish winter, grow this.

Why Scotland suits kale

Kale is the most dependable winter crop in a Scottish garden, and the reasons are worth knowing because they change what you need to watch for.

Our cool summers hold down cabbage aphid and cabbage root fly, the two pests that torment brassica growers further south, and plants mature more slowly and steadily here. Flea beetle, which shreds brassica seedlings elsewhere, needs warm, dry, still weather and gets knocked back by rain, so a wet Scottish spring protects your seedlings for free. The risk window is a dry warm spell, not the whole season. And kale is among the hardiest leafy vegetables there is, standing through the coldest months without protection.

This is a crop whose enemies dislike our weather, cropping in February when the alternative is an empty bed. The pest advantage comes from field-scale guidance covering brassicas as a group, so take it as the direction of travel rather than a guarantee for kale specifically.

Choosing a type

Kale comes in more forms than most people expect, and the differences are real rather than cosmetic. Choose the type before the variety: it settles how much space the plant needs and how it will taste.

• Curly or frilly types are the familiar ones, tough and very hardy.
• Cavolo nero, also sold as Nero di Toscana, has narrow dark puckered leaves and a milder flavour.
• Compact varieties suit small beds and containers.
• Perennial kales such as Daubenton's and Taunton Deane crop for years rather than being resown. Most kale is biennial; these are the exception, and worth knowing about if you want a permanent corner of the plot working.

The type you chose above matters at least as much as the variety. All of these carry the RHS Award of Garden Merit, a UK-wide award rather than a Scottish one.

Also worth considering

Soil, and why liming matters here

Lime the bed. It is the single most useful thing you can do for kale in Scotland, and it buys two things at once: kale prefers soil limed towards neutral, and clubroot is far less of a problem in alkaline ground. Our soils are naturally acidic, so a cheap soil test and a bag of lime is the best insurance available against the one disease that has no cure.

Keep your potatoes elsewhere in the rotation, though. Liming pushes up their risk of scab, so this is a trade between two beds rather than a free win.

Otherwise: weed thoroughly, dig in plenty of well-rotted manure or garden compost, rake level, and then firm it well. That last step gets skipped and it matters. Kale grows tall and top-heavy, and loose ground gives it nothing to hold onto.

Sowing

Sow indoors from March, or outdoors from March to June, about 1cm (½in) deep. Raising plants in modules or a seedbed and moving them later is the easier route, because small plants are far simpler to protect than a whole sown row.

That long window is part of why kale is so forgiving. A June sowing still returns a crop, which is not something you can say about much else grown here.

Planting out

Move plants to their final positions at 10 to 15cm tall, usually late spring or early summer, spaced 30cm to 60cm apart depending on variety. Compact types take the lower end, large types the upper. For baby leaves as a cut-and-come-again crop, 7.5cm is plenty.

Firm them in hard, and in autumn push a sturdy cane in beside tall varieties on exposed sites. A mature kale plant in a Scottish gale is a sail, and one that rocks all winter loosens its own roots and lets rot in at the base.

Netting, and the pigeon problem

Net the crop at planting and leave it on through winter. Insect-proof mesh over hoops or canes stops caterpillars, cabbage root fly and pigeons together, and it is far more effective than dealing with any of them afterwards.

The winter part is where Scottish growers lose crops. Pigeons do their worst damage when other food is scarce, which is exactly when your kale is the only green thing standing in an empty garden. A plant that sailed through autumn can be reduced to stalks in January. Take the netting off once the caterpillars have gone and you have handed the crop to the birds.

Watering and feeding

Water seedlings and new transplants until they take hold. After that kale needs water only in prolonged dry spells, which in most Scottish summers means rarely. Containers are the exception and need attention across the season.

Feeding is usually unnecessary. Ground with plenty of compost dug in will carry the crop, and only poor soil or containers need a nitrogen-rich organic feed.

Clubroot, the one that lasts

Clubroot is the only kale problem serious enough to change where you garden. Plants come up stunted, wilt in sunshine and recover overnight, and lift to reveal swollen, distorted roots.

There is no treatment, and once it is in a bed it stays for years. The risk runs high in Scotland because clubroot is worst in wet ground with a low, acidic pH, which describes a great many gardens here. Drainage and pH are the levers that actually work, which is the second reason to lime.

Then keep it out: do not move soil, tools or plants from an affected bed to a clean one, and be wary of accepting brassica plants raised in someone else's ground. Most clubroot arrives as a gift.

Harvesting

Start picking from September, taking two or three of the lower leaves from each plant rather than stripping any one of them. Leave the growing point alone and the plant keeps going for months, through winter and into spring. Regular picking encourages more growth, so the plants you visit often will outlast the ones you forget.

Kale is at its best in the depths of winter, and many growers find the flavour sweetens after frost. Come spring the plants run to flower, and the shoots at that stage are worth eating like sprouting broccoli before you pull them out.

Common problems

Kale is not a troublesome crop here, and the mesh you fit at planting deals with most of this list before it starts.

• Clubroot is the serious one, covered above.
• Cabbage white caterpillars can strip a plant to the ribs in a fortnight. Rub the clusters of yellow eggs off the undersides of leaves and it takes seconds; wait for grown caterpillars and it takes weeks.
• Flea beetle peppers seedling leaves with small round holes, as though someone fired birdshot at them. Established plants shrug it off.
• Slugs and snails go for young transplants, which is another argument for setting out sturdy module-raised plants.
• Pigeons in winter, as above. Netting, not hope.
• Wind rock loosens tall plants over a winter of gales and lets rot in at the base. Stake them, and re-firm the soil after a storm.

Common questions

Sources