Chinese cabbage is an excellent crop for late summer when days are long and nights warm. At other seasons it bolts readily and is satisfactory only as mini leaves.
Sow in very fertile soil and water carefully to ensure good growth and to suppress bolting. Sow thinly outdoors from June to August, every three weeks for successional crops, 1cm (½in) deep in rows 38cm (15in) apart.
Thin seedlings to 30cm (12in) apart for large heads or to 15cm (7in) apart for ‘cut and come again’ salad leaves.
Chinese cabbage needs a deep, moisture-retentive soil and a firm bed on an open sunny site; it benefits from some shade in summer. Add manure and fertiliser before sowing.
Acidic soils should be limed if necessary as this crop is very susceptible to clubroot disease – a fungal organism suppressed by alkaline conditions.
Water before the onset of drought, to keep the soil moist and prevent ‘bolting’.
Keep soil weed free.
Cabbage root fly: White larvae approximately 5cm (2in) long, feed on the roots just below the soil surface, stunting growth and causing plants to wilt and die.
Remedy: Grow under insect-proof mesh or horticultural fleece. Seedlings are most vulnerable.
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Flea beetle: Leaves are covered in small holes and damaged areas turn brown. Seedlings are particularly susceptible.
Remedy: Grow plants under horticultural fleece and keep the soil moist. Water in nitrogen-rich fertilser to help the crop outgrow the pest.
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Club root: Roots become swollen and distorted, and leaves become pale and yellow and wilt easily. Plants may die.
Remedy: Improve drainage and add lime to make soil more alkaline. Do not grow in affected soil.
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Slugs and snails: These feed on the young seedlings and you'll see the tell tale slime trail on the soil around your crop, as well as on the leaves.
Remedy: There are many ways to control slugs and snails, including beer traps, sawdust or eggshell barriers and copper tape.
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Caterpillars: 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.
Remedy: In mild attacks, or if you have only a few plants, you may be able to pick the caterpillars off. You can spray with pyrethrum, deltamethrin or lambda-cyhalothrin. Insect-proof mesh or fine netting (5-7mm mesh) can prevent egg-laying.
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Harvest ‘cut and come again’ crops, from seedlings to semi-mature plants, using scissors or a sharp knife. Plants that are harvested once the root has established will re-sprout several times then finally ‘bolt’. When this happens, harvest the flower heads before they start to open, as you would broccoli.
Most cultivars form hearts well, but some might need binding. Tie up the heads of hearting varieties with soft twine or raffia when they reach maturity. Protect maturing plants with cloches, from autumn onwards, to stop moisture from rotting the heart.
Mature heads can be cut and stored in a frost-free shed or refrigerator. Remove the head and leave the stump to produce more, smaller heads or ‘cut and come again’ leaves.
‘Early Jade Pagoda’ AGM: A cylinder-shaped or ‘Michihili’ type. Uniform, with dark-green outer leaves and a short internal stem. Late maturing.
‘Kasumi’ AGM: High yielding and barrel-shaped, with solid heads and pretty green outer leaves.
‘Questar’: Medium-large with dark green outer leaves and firm. Slow to bolt and can be harvested around 65 days from sowing; claims to be club-root resistant.