Superfood status has made Kale, an old-fashioned favourite, a must for every winter garden
Kale has risen from relative obscurity to become a very trendy vegetable in recent years. It’s even sold by the bunch in supermarkets and turns up on many restaurant menus. Much of this renewed interest comes down to its reputation as a “superfood”. This leafy vegetable is packed with vitamins (including vitamin C, carotene and folacin), is rich in calcium and iron and is a source of dietary fibre.
The good news is you don’t have to shop in the supermarket aisles or dine out to enjoy kale and benefit from its nutrients. This old-fashioned green is easy to grow with a little care, crops over a long period and is handy to have growing in winter and spring when fresh greens can be scarce. Kale is also very ornamental and appeals to those who like to grow heirloom vegetables. Varieties have been grown for centuries, reinforcing this vegetable’s heritage appeal. Some forms also have multiple names.
Some kales develop a thick stem topped by a rosette of cabbage-like leaves, while others are more compact with a rosette form. Best known is Tuscan kale, also called Cavolo nero or Lacinato, which has long, quilted, slate-grey leaves. The leaves have the look of a small palm frond, which leads to another of its common names of black Tuscan palm. It forms a tall clump to around 60cm high and 30cm across and has long been used in Italian cooking, particularly, of course, in Tuscan recipes.
Other varieties include Red Russian, also known as Ragged Jack, which has frilly leaves and purple stems, while Squire has frilly blue-green leaves. Blue Curled Scotch kale has distinctly curled blue-green leaves, which forms a decorative element in the winter vegie garden. These kales grow to around 40–60cm high and 30cm wide. Many garden centres offer mixed punnets of kale to give access to the wide variety of colours and forms available.
As well as edible kales, there are also cabbage-shaped plants that are grown solely as ornamentals favoured for their long-lasting and pretty foliage. These ornamental forms may have green leaves marbled with pink, purple or white and sometimes all these colours come together in a vibrant mix. Coloured ornamental kales are sold under names such as ‘Winter Wonder’ and are useful as potted plants or to mass among annuals for autumn and winter colour in garden beds and are not usually eaten.
Kale is part of the large brassica or cabbage family that also includes broccoli, Brussels sprouts, cabbage and cauliflower along with lesser-known and perhaps soon-to-be-trendy green collards. Like these other brassicas, kale does best in a cool climate but it’s also worth growing through winter in warmer climates. It’s particularly useful to grow through winter in areas with cold winters when little else grows. Although it isn’t worried by cold or frost, it keeps growing as the weather warms. In crop rotation, kale and other brassicas can follow legumes.
How to grow
Kale grows best through the cooler months, so seeds are planted in summer and autumn. Seedlings are planted from autumn to spring to keep a good supply of greens growing through winter. Seeds can be direct-sown where they are to grow, or started in seedling trays and then transplanted into the garden bed. Sow seeds at about 2cm depth and space seedlings 40–60cm apart, depending on the size of the variety being grown. Like all brassicas, kale prefers a neutral to slightly alkaline soil (pH around 7). For acidic soil, digging in dolomite or lime while preparing for planting improves growing conditions. Also dig in compost and manure or an organic fertiliser before planting, to feed the developing plant.
Keep seedlings well watered as they establish. To promote strong growth, feed the developing plants monthly, providing a side dressing of organic fertiliser (such as pelletised chicken or blood and bone). Alternatively, apply an organic liquid-feed fortnightly.
Its susceptibility to pests and some diseases is what lifts kale from easy to moderate on the ease-of-growing scale. Cabbage white butterfly caterpillars, aphids and club root are all problems that may be encountered when growing kale. Regularly searching over the foliage and removing the green caterpillars by hand is the best organic remedy, but large infestations can be treated with the organically acceptable Bt (sold as Dipel) or spinetoram. Club root is harder to combat but can be controlled by growing plants in alkaline soil (club root favours acidic soils) and by following crop rotation principles so brassicas are not grown in the same garden bed for several seasons. Kale that is heat or water stressed may also be tough to eat.
Harvest and use
Kale is a biennial plant that keeps growing and can be harvested throughout the year. Harvesting can begin at around seven to eight weeks after planting or when the plant has produced enough leaves so some can be picked without affecting the plant’s growth. Harvest leaf by leaf, as needed. This is a versatile vegetable. It can be cooked like spinach, added to soups or sauces, or individual or torn leaves can be fried or baked as a chip. It can also be juiced or used in pickles.
Written by Jennifer Stackhouse
Originally in Good Organic Gardening Volume 8 Issue 1