How to plant and grow Kale

When I was a child, kale was only associated with the fields grown for winter fodder for the cows. It was scarcely human food. But the black Tuscan kale – cavolo nero (although also labelled as ‘Nero di Toscana’) – is as delicious as any cabbage. However, unlike cabbage, it has the distinctive characteristic of remaining good even when boiled for a long time. This means that it can be added to minestrone or the delicious and typically Florentine bread soup, ribollita. Kale also reheats very well and, mixed with garlic and cream, makes a fabulous sauce for pasta. It is versatile and delicious and high in nutrients. What’s not to like? 

Kale produces a sheaf of more or less upright leaves from its central stem. These leaves are tough – hence its hardiness. They need boiling for up to half an hour although a really hard frost does a lot to break down that toughness and improve the flavour. Nevertheless we eat it all the year round. 

I make my first sowing in January, under cover, and plant the seedlings out just 2.5–5cm (1–2in) apart in late March. They germinate very easily and can be sown direct in a seed bed as soon as the ground warms up. My first sowing is picked very young and used as part of a mixed salad, never growing more than 7.5cm (3in) or 10cm (4in) tall, and is cleared by the middle of May. This is when the next batch, sown in mid-March, is planted into the position that it will occupy for the next twelve months. It does best with 60–90cm (24–36in) between each plant and needs staking from midsummer. 

The secret of kale is to eat the leaves when they are a reasonable size but not too old – when they really are suitable only for ruminating cows. So I pick a handful of leaves from half a dozen plants at a time, working across the whole crop before returning to the first plants at the next picking – by which time they will have produced another batch of leaves. They are very satisfying to pick, yanking them down from the central stem with an audible snap as they come away in your hand. This way each plant will provide half a dozen or more pickings between September and April. 

Curly kale is much tougher to eat and harder to digest but looks magnificent. Red kale, such as the plum-coloured ‘Redbor’ or ‘Red Russian’, which has grey-green foliage with deep purple stems, is even more handsome and I grow it for its decorative value alone, although I always eat some almost as a matter of principle. But the truth is that I always return to the wonderful cavolo nero.

Family	Brassicaceae
Growing zones	N/A
Growing season(s)	cool weather: spring, fall, winter
Spacing	12 to 18 inches
Start indoors or direct sow	either
Indoor sowing date	6 weeks before transplant (10 weeks before average last frost)
Earliest outdoor planting	4 to 6 weeks before average last frost
Soil temperature	45° to 85°
Fall planting	start indoors 12 weeks before average first frost and transplant 6 weeks before average first frost; or direct sow 4 to 6 weeks before average first frost
Sun needs	6+ hours, can tolerate more shade in the summer
Water needs	moderate
Harvest category	all season in the fall/winter for many areas; weather dependent in spring
Fun Fact:	One cup of raw kale provides more than 100 percent of the daily recommendations for vitamins A and K.

 

Snapshot	The poster child for healthy eating, kale can be grown in most gardens at a time when garden space is most available. Kale prefers cold weather, and therefore tastes better when harvested after a frost, making it a prime fall crop. But it can also be planted in the spring and enjoyed before summer crops make their appearance.
Starting	Kale can be started indoors both in the winter (for spring planting) and in the summer (for fall planting) to get a jump-start on the season. It also grows well when sown directly into the garden. Sow seeds 3 inches apart and thin to a final spacing of 12 to 18 inches.
Growing	Kale loves a rich, fertile location with a pH above 5.5 and grows to maturity in about two months. It requires consistent moisture, because its roots are shallow and prone to drying out. Dry roots are especially a concern in the fall, when young plants have grown in a hotter, dryer part of the season. A good layer of mulch will help prevent evaporation, and it will also insulate the soil in the colder parts of the winter, extending the harvest. In most areas, kale will survive the winter; growth will slow or stop in the darkest days, but it will start growing again as daylight increases.
Harvesting and Storing	Like lettuce and other leafy crops, pick young, tender leaves from the outside in. Kale will continue to produce from the inside. Store the leaves in the refrigerator or freezer. Many people find dehydrated “kale chips” a fun treat.
Common Problem	Heat in the summer will toughen the leaves of kale, and often it will bolt in hot weather, sending up flower stalks. To get the most of your harvest, grow kale as a fall crop or plant it in early spring. Then, plan to replace it with a succession planting of a heat-loving plant as the weather warms in the summer.