Ever been told to ‘eat your greens’? Well, kale is one of the most nutritious vegetables you could possibly grow. It’s crammed with vitamins and powerful antioxidants - and it tastes delicious! It also just so happens to be the easiest brassica of all to grow. What’s not to love about kale?!
But while it’s certainly easy to grow there are a few crucial things to get right if you want to enjoy a truly bumper crop of health-boosting leaves.
Types of Kale
Kale comes in a stunning range of varieties, from bright greens to dark purples, crunchy leaves to crinkled beauties and everything in between. There are so many amazing flavours and textures to choose from that you just won’t find in the supermarket: mild, almost salad-like greens, sweet ‘Red Russian’ kale, or the nutty and sometimes peppery flavours of Italian kales. My favorite? The dashingly handsome ‘Cavolo Nero’ or Tuscan kale, often called dinosaur kale because of its texture.
Starting Off Kale
Because the spacing between kale plants is quite wide, at around 18in (45cm), it’s preferable to start kale off away from the main growing areas to make more efficient use of space. It means you can then be growing something else in the ground, while your kale is still at the seedling stage elsewhere.
The way I see it you have two strategies for growing kale: sow in spring for harvests from summer onwards, or sow a few months later on in early summer to crop from later summer and on through winter.
Spring sowings will be ready to plant a month or so after germinating. They will grow quickly but may be a little more vulnerable to attack from caterpillars. On the other hand, summer sowings won’t go into their final positions until later in summer when caterpillars are less of an issue. Also, this timing makes it the perfect succession crop to follow on from earlier staples such as carrots or broad beans.
You can sow them in a nursery bed to dig up and transplant into their final positions later, but I prefer to start them off in pots or plugs trays under cover. This way they there’s less risk of them getting mown down by slugs or left ragged by flea beetle.
Use any all-purpose potting mix, and either sow into pots to transplant into plug trays, or sow direct into plug trays – a few seeds per plug then thinning to leave the strongest. Grow on until it’s time to plant them outside, usually when they have a few sets of adult leaves. If the ground is still occupied by an earlier crop when they’ve outgrown their plugs, just pot them on into a larger pot to keep them ticking over.
The Effects of Sunlight on Kale
Sunshine has a direct effect on both the success and taste of kale. Kale grows best in full sunshine, particularly in temperate climates like mine – after all, it’s access to good, strong light that powers growth. In the height of summer however (particularly in hotter climates), full sun can encourage more bitter-tasting leaves, but grow them where they’ll get a little more shade and you’ll find the leaves are a lot milder to taste. To be honest, kale seems far from fussy on this front. I grow kale in dappled shade and find that the plants do really well. They seem to love the moister soil conditions that this offers – after all, this is a cool-season crop.
Wherever you’re growing kale it will appreciate a relatively free-draining soil that has been enriched with plenty of organic matter. One of the best ways to sustain strong growth is to spread an organic mulch (for instance compost) around plants during the growing season. In hot weather this will help to keep the soil cool and moist, then as it breaks down it will help to improve the conditions of your soil deeper down, giving plants a boost as they head into winter and then when growth gears up again in spring.
Kale prefers cooler, wetter summers, so if a dull summer means heat-lovers like tomatoes are a bit lacklustre, at least you’ll have one crop that will come up with the goods! If the weather is dry, remember to water well to keep growth steady and avoid bitter-tasting leaves. Plants that are well fed and watered will be better placed to withstand pest attacks, which brings us to our next topic…
Sidestep Insect Pests
One of the most notorious issues when it comes to growing any of the brassicas, including kale, are the various pests it attracts. It seems that just about anything and everything wants to eat it: those clouds of whitefly that take to the air if disturbed; cabbage aphids; cabbage white butterfly caterpillars that devour foliage with alarming efficiency; and flea beetles, which tend to attack younger, more tender foliage earlier on in summer.
Early aphid infestations can simply be clipped off and composted to try and contain them. Check plants a few times a week during the summer, searching for caterpillars of the cabbage white butterfly. Pick off any you find. They can be despatched in a bucket of soapy water. Don’t forget to check the undersides of leaves, because more often than not this is where they lurk to avoid birds. Growing the darker or purple types can help you to spot many pests early, because they stand out more.
Take advantage of companion plants to help reduce pest problems. For instance, nasturtiums can help to lure the butterflies away from your kale, while thyme is said to confuse them. The best course of action however is to simply keep plants covered, using covers of horticultural fleece, fine mesh, or butterfly netting. As well as insect pests, it will also help keep birds like pigeons off, which can be a particular problem in the winter.
But don’t fret too much if plants do get attacked. Kale is a resilient vegetable that soon springs back to its full glory the moment colder weather arrives, when pests are either killed off or hunker down for the winter.
How to Harvest Kale
Younger leaves picked earlier on in the season are really quite tender and jolly good in salads, particularly the softer-leaved kales such as ‘Red Russian’. Kale will stand in the garden through very harsh winter weather, and frosts actually help to develop its flavour by turning starches into sugars. As plants grow, after many harvests, you’ll be left with a long stem below the leaves. Sometimes plants start to get a bit top-heavy because of this, so you may need to tie them to canes for support.
The best way to harvest kale is to take the outermost leaves, which as the plant grows will tend to be the lowest on the plant. The leaves will need to be stripped off from the tough central midrib. Together with the unflappable chard, I’d say kale is my favourite leafy green. It’s so forgiving and so delicious – try it massaged with a little olive oil and paired with winter squash and toasted pumpkin seeds. Delicious!
Harvest leaves as you need them to ensure the absolute peak of freshness, but if you do need to store them, keep leaves whole in the refrigerator (preferably in the salad compartment or crisper drawer) for up to 10 days.