Similar to traditional sprouting broccoli, this East Asian vegetable has tender edible stems, leaves, buds and flowers. Also known as kai lan, it is a fast-growing crop that is a great source of antioxidants and vitamin C.
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Sow seeds outdoors between April and September into weed free, well prepared soil.
Plants prefer an open, sunny site – if soil is very acidic, raise the pH by adding lime.
Sow seeds lightly in a 2.5cm (1in) deep trench, thinning seedlings to 30cm (12in) apart when they are large enough to handle.
Alternatively, scatter seeds over the surface of large pots filled with compost, cover and treat as a cut-and-come-again plant, harvesting young leaves for salads.
Water plants well, especially during long, dry periods over summer.
Keep soil clear of weeds to prevent competition.
Allow the odd to plant to flower, rather than harvest. It is a great source of nectar for bees and other pollinating insects, and the edible flowers make a great garnish.
Plants grow quickly and are ready for harvesting just a few months after sowing – generally between July and November, and, in fact, early sowings flower rather prematurely. This doesn’t matter – just use what you can and sow more.
Cut the top few centimetres off with a knife when the white flowers appear. The stems can be cut into small sections, blanched in boiling water, then added to stir-fries.
Harvest young leaves from cut-and-come-again sowings as required.
A number of caterpillars will feed on brassicas, but the most common are those of cabbage white butterflies. You will usually see the caterpillars, if not, you will see the holes they make in the leaves. They will also bore into the heart of cabbages.
In mild attacks, or if you have only a few plants, you may be able to pick the caterpillars off. Insect-proof mesh or fine netting (5-7mm mesh) can prevent egg-laying.
Roots become swollen and distorted, and leaves become pale and yellow and wilt easily. Plants may die.
Improve drainage and add lime to make soil more alkaline. Do not grow in affected soil.
Plants flower and set seed prematurely.
Unless growing for seed sow bolt-resistant varieties. Sow or plant at the correct time and keep the soil or compost moist.
The Royal Horticultural Society is the UK’s leading gardening charity. We aim to enrich everyone’s life through plants, and make the UK a greener and more beautiful place.