Asian brassicas are tasty, quick-growing (60-90 days) and suit late-summer sowing for autumn crops. Pak choi, in particular, is becoming especially popular. They can follow early crops of peas or salads that leave the ground free by late summer.

In fact, sowings before midsummer tend to flower prematurely (“bolt”) and those from late June are more reliable.

September sowings might not grow sufficiently before duller, cooler weather halts growth. However, Asian brassicas do lend themselves to growing as baby leaves, taken when 10cm high, and are good choices for September sowing.

Packets of mixed seed are sold for this purpose. Brassica seed can last for seven years if kept cool and dry, so it is worth buying a range of types and keeping leftover seed for subsequent years.

Botanically, many Asian greens are related to turnips (Brassica rapa), itself a fine, speedy late-summer vegetable. In Asia, Brassica rapa greens were bred and selected by Asian growers over millennia to make distinctive crops.

Western brassica are mostly derived from the common seaside plant Brassica oleracea, with most cultivated forms arising in Italy. Swedes and oilseed rape are derived from B. napus, a hardier species than the somewhat frost-sensitive Brassica rapa.

Pak choi, with its spoon-shaped leaves and bulbous base of white leaf stems (petioles), is best eaten when lightly boiled, steamed or stir-fried. Green, lime-green or red-leaf cultivars are available.

Bolting is triggered by fluctuating soil moisture, hot weather and stress when transplanted. Ideally, sow the seed where the plant is to grow, thinning to 25cm apart and allowing 30cm between rows. Smaller cultivars can be spaced slightly more closely. Adding composted manure or garden compost before sowing produces the rich, moist soil favoured by this crop.

Tatsoi and choi sum are leafy, often crinkly savoyed leaves, and flowering relatives of pak choi, and are grown and used in the same way.

Asian brassicas benefit from covering throughout the crop’s life, with fine insect-proof mesh or garden fleece, ideally biodegradable, to exclude unwelcome insects that are most numerous in late summer. Slugs and snails can be troublesome in wet summers, when nematode preparations can be watered on to protect the plants.

Clubroot-resistant pak choi and Chinese cabbages (above) are available, including “You Qing Choi” and “Yuki” respectively – ideal for allotments where this disease can be common.

Chinese cabbage, with its cos lettuce-like hearts, is grown in the same way as pak choi but allows more space – 50cm between plants and rows. As well as pale-green elongated forms, barrel-shaped and red-leaved cultivars are offered.

The tight heads of Chinese cabbage store very well in cool conditions – the salad compartment of the fridge, for example – helping to reduce wastage.

Mustard greens (Brassica juncea) and mizuna, a Brassica rapa crop, grow into loose leafy vegetables which are notably tangy, nutritious and relatively hardy, so are a good choice for early-winter cropping. They are used in salads or lightly cooked.

Chinese kale – also known as kailaan or kichi (B. oleracea) – is grown for its delicately flavoured flowering shoots and succulent stems, taken just before the flowers open, and eaten raw or lightly steamed or stir-fried.

The plants produce a single flowering shoot, much smaller than calabrese but more flavoursome, and arguably under-appreciated.

Make sowings in succession every two weeks, allowing 20cm between plants and 30cm between rows in fertile soil, as recommended for pak choi.

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