Kale

Kale (Brassica oleracea Acephala Group)

Kale has been touted as a superfood and is a trendy ingredient for a variety of salads and smoothies. There are many varieties of Kale; the leaves can be curly or smooth, and come in a range of colours, including purple, blue-green, and even white.

This crop can be perennial or annual, depending on the variety.

Kale has a generally shallow root system, but the plant can grow quite tall. It can be grown in containers but will require staking as the plant grows taller.

Kale is part of the Brassica or cabbage family, which also includes other popular vegetables like cai xin and kai lan.

Sun and soil needs:

Kale grows best in about 4-6 hours of direct sunlight or at least 6 hours of indirect sunlight. Kale should ideally be grown in areas with morning or evening sun, as the heat from direct sunlight during mid-day tends to make the plant bitter. Consider using netting to protect the plant if it is exposed to the mid-day sun.

Plants do best in pots with loamy soil at least 15cm deep, or in true ground. These plants are vulnerable to root rot, so ensure that your pots drain well, and that your soil has plenty of organic matter to let the roots breathe. Keep your plants cool with mulch and plenty of water to encourage growth.

Sowing seeds:

Sow seeds individually in a seedling tray filled with potting mix or seedling mix. Lightly mist the soil until damp, once a day. Seeds should sprout within two weeks.

The seedlings will be vulnerable to high heat and heavy rain and are best kept in a sheltered propagation area or a shaded space with around 4 hours of partial or direct sunlight.

The seedlings may be eaten by snails or birds. Protect your young plants with a DIY cloche or netting.

Transplanting:

Seedlings will be ready for transplanting into pots or true ground when they have developed 4 or more leaves, or roughly a week or two after germination. Leave 15-20cm between each plant to encourage more growth, better ventilation, and prevent etiolation.

Growing:

Kale is a rapid grower and will produce more leaves if fed with high nitrogen fertilisers. Plants can be fertilised once every two weeks after transplanting for a fuller crop.

Kale can grow very tall with time and should be supported with a stake to prevent the main stem from snapping.

Harvesting:

Plants can be harvested for leaves, with younger leaves being the most tender. Most gardeners will begin harvesting from their kale plant around a month after sowing.

Kale is typically harvested multiple times by harvesting the older leaves as per the cut-and-come-again method. Perennial cultivars of kale can live for several years if cared for properly and will continue to produce new leaves year-round.

Harvest cycle:

Propagation:

Kale is primarily grown from seeds, but it can also be regrown from rooted stems. Some varieties of kale also produce offshoots that can be planted.

Common problems & solutions:

Young plants have soft stems and can be completely eaten by slugs and snails. Grow seedlings till they are at least 10cm tall before planting them in true ground, or use DIY cloches or netting to protect young plants.

Caterpillars, usually from the Diamondback moth and Tussock moth, can rapidly eat all the leaves of your plant. If your plant has lots of large holes and small brown or black fecal pellets scattered around damaged leaves, you likely have a caterpillar infestation. Manually remove the caterpillars by hand and protect your plants with netting.

Leaf miners are fly larvae that eat the leaves from the inside, leaving white lines or patches in their wake. Manually remove damaged leaves and use fine mesh netting to stop the adult flies from laying eggs on the plant again.

Etiolation is characterised by plants growing long and skinny, with weak stems and small leaves. The plants may also sometimes look yellowish. Plants etiolate when they do not get enough sunlight, which results in slow growth and untidy forms. To prevent this, grow plants in environments with enough light for them and make sure that each plant has enough space to prevent overcrowding.