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Alan's Edible Plant of the Month - Kale

Published on November 6th 2019

by AlanGardenMaster. All rights reserved

A close up of kale
In recent years, kale has become one of the most popular vegetables to grow, and you can harvest it nearly every month of the year. Arguably at its best in November, I had no difficulty in choosing kale to be my edible plant of the month.
When I was a child, the only kale that I would frequently come across was grown as winter cattle feed. It was either the 'Marrow Stem' or 'Thousand Headed' varieties. I recall that 'Marrow Stem' had a sweet, fresh core inside the fat stems, and I would eat it raw. 'Thousand Headed' types had, yes you've guessed it, several growing points.

Varieties to Grow

You'll see kale and borecole varieties listed here, but what's the difference? There are some slight variations, but borecole is a form of kale, so this shouldn't worry us!
'Nero de Toscana' looks as good as it tastes. It has narrow strap-like leaves with rolled down edges and dark green, heavily puckered leaves that have almost a blue sheen. You can harvest this variety from September to February by removing the lower leaves first. This kale is sometimes called 'Black Russian.'

Cavolo Nero

Brassica oleracea (Acephala Group) 'Bumpy-Leaf Kale'

Kale plants in a garden
'Nero de Toscana' and 'Redbor' borecole
Kale 'Westland Winter Borecole' has very curled leaves and makes quite a big plant. You'll be able to harvest from it all winter as it's very hardy. There's an excellent dark purple version too.
'Dwarf Green Curled' has a very telling name! It is very frizzy and curled, with deep green leaves on plants 50-60 cm tall. Since they are short, this variety is ideal for windy gardens. It certainly needs no staking - best harvested between September and February.
'Midnight Sun' is a variety that has been popular as an ornamental plant for its lovely pinkish purple midrib. You'll sometimes see it in containers with primroses, pansies, wallflowers and other winter bedding plants. But it comes into its own as a leaf salad plant. It's possible to harvest 'Midnight Sun' from October to February.
Similarly, 'Emerald Ice', once popular as an ornamental, is now being grown more for salad leaves. In this case, the midrib is cream coloured.
White kale plants
Emerald Ice kale
My favourite kale is actually a hybrid between kale and Brussels sprouts! They are often sold as 'Kalettes', and I love them! They are much easier to grow than sprouts and have a flavour somewhere in between the two. I find the best way to cook these is open roasted after drizzling with olive oil.
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Plant raising

The traditional way to grow kale is to sow in rows - often called 'drills' - and transplant them to the final growing position when the plants are big enough.
Sow seed during May, June and July, and when plants have 3-4 true leaves not counting those little heart-shaped seed leaves. You can dig them out and plant the strongest about 60 cm x 60 cm apart.
Plant into well-prepared soil which has had weeds removed, been thoroughly dug and allowed to settle. You can also add a general balanced fertiliser such as Vitax Q4.
Plant the seedlings deeply so that the soil level touches the lower leaves. This will help to prevent plants rocking in the wind when they get bigger.
If you're growing the no-dig way, then you'll need to be planting into a new layer of compost laid on top of the soil.
Increasingly more gardeners are raising their kale and other seedlings in cell packs or modules. Kale has quite a large seed, so it is practical to place one seed in each cell, to maximise your growing space.
module grown seedlings
Kale seedlings in modules

Where to Grow Kale

Toscana de Nero kale bunches
'Nero de Toscana kale
Kale will grow well in any well-drained soil but prefers alkaline soils. So aim to increase your soil pH to 6.5 or over by adding lime. Soil test kits to test the pH are widely available and easy to use.
Growing kale and other members of the Brassica family in the same place year after year can lead to disease problems, so try to rotate the place where you grow them.

Kale as Salad Leaf

You'll often find kale mixed in with other salad leaf varieties such as mizuna, types of mustard and lettuce. When harvesting, try to leave the growing point to extend the harvest.
With all salad leaves, I find that it's a good idea to sow another batch just as soon as you start harvesting.

Perennial Kale

It's possible to harvest tasty kale from perennial kale all year-round.
'Taunton Deane' kale (Brassica oleracea var Acephala) is an extremely old variety of perennial kale. It will overwinter and keep on growing for years! Some people call it cottager's kale, and it was a popular vegetable grown right up until Victorian times.
I recently saw 'Taunton Deane' kale at charles_dowding's garden, and he said that seed was no longer available and can only be grown from cuttings.
Perennial kale Taunton Deane
Perennial kale Taunton Deane
I've noticed that Kings Seeds of Kelvedon in Essex still list seed of a 'Cottager's Kale', so perhaps they are worth trying.

Some Ways of Eating Kale

There are quite a few ways to enjoy kale, but my favourite is to bake in the oven. Place individual leaves uncovered on a flat tray, drizzle with olive oil and lightly season. Place into a really hot oven for a few minutes until the leaves are crisp. This technique traps in all the flavour.
If you like your kale cooked a more conventional way, then you can steam it, but please never boil! This might be a personal thing, but a lump of soggy boiled kale is most likely to still be on my plate at the end of a meal!
Of course, kale can be eaten raw.
Rows of kale and mizuna in a garden
Winter rows of salad leaf kale and mizuna

Nutritional Value

I don't profess to be a dietary expert, but I do know that kale is full of pro-vitamin A, vitamin C, iron, folic acid and calcium.
Good Housekeeping has summarised the benefits here so take a look.
Bunches of cut kale
Bunches of cut kale
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Pests to look out for

Pigeons, caterpillars, whitefly, mealy aphids, aphids, slugs and snails, flea beetle and cabbage root fly - the list seems endless!
But kale is less likely to be troubled by pests than other members of the cabbage family!
You can use large mesh in the winter to protect against pigeons, and small mesh in the summer to defend against caterpillars. You could spray with Grazers to ward off the pigeons (a calcium-based environmentally sensitive product) and garlic spray to deter caterpillars.
Curly kale covered with bird netting
Curly kale covered with bird netting
If you do see caterpillars on your kale, you could use a biological method of control called B.T., a bacteria called Bacillus thuringiensis. It's not widely available in the UK so you might have to source from overseas. Look for a product called Dipel.
The sap suckers (aphids, whitefly, mealy aphid) will be deterred by regular sprays of garlic which you won't be able to taste on your kale!
Cabbage root fly larvae feed on the roots and can cause sudden collapse. A tight-fitting physical barrier around each plant will prevent the flies laying eggs in the soil.
Flea beetles feed on the seed leaves and can have a significant detrimental impact. Raising your plants in modules under cover can help.
Slugs and snails can be a menace. I find that organic slug pellets based on ferric sulphate are very effective and are safe to wildlife. I have used these for almost 20 years and have been very impressed with the wildlife that I find among my plants. Under no circumstances be tempted to use the old metaldehyde based pellets!
Mixed kale plants
Mixed kale plants

Diseases to guard against

Clubroot is the biggest disease to be aware of. It distorts the root system causing ugly swellings. The disease is very persistent in the soil so regular crop rotation is essential. Raising the soil pH above neutral by adding lime prior to planting has a big impact on reducing this disease.

Not just for the Veg Patch!

Some varieties of curly kale look great when planted in flower borders! If you don't have a veg garden then you cal always plant them in between the flowers and in containers.
A purple kale plant
Purple kale plants are decorative too

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