THERE’S a whole group of leafy vegetables which grow better when sown after the longest day, rather than before. 

They are all brassicas, and therefore members of the mustard family, and so have, to varying degrees, hot or cabbagey flavours. 

You’ll usually find the seeds and young plants listed in catalogues and online under oriental greens, or as mustard greens. 

Sometimes the words Chinese, Japanese or Vietnamese are added — more or less randomly, I suspect, and determined mostly by which cuisine is currently fashionable.

July and August are the main sowing times for many of these valuable vegetables, which will be ready for harvesting, variously, from late summer through to winter. 

As allotment beds are cleared of early potatoes and onions, space becomes available which the mustards fill very nicely.

Pretty well all of the oriental greens can also be grown in pots. They don’t need particularly large containers, but remember that the smaller the volume of compost in the pot, the more frequently it will dry out. 

Big patio tubs, which take 30 or 50 litres of compost, won’t need watering as often.

All of these seeds can be sown directly in the ground, and later thinned to the spacings given on the seed packet. 

Most of them can also be started off in trays or modules to be planted out later.

There are a number of potential problems with growing leafy crops at this time of year, which may or may nor arise depending on the weather, your location, and your luck. 

Caterpillars and tiny flea beetles will both want to eat the leaves. They can be defeated entirely by carefully covering the plants with horticultural fleece, but that does cost money. Some people use old net curtains to do a similar job.

The crucial thing with these late summer vegetables is to keep them growing steadily and rapidly, and that means above all keeping them watered. Regular and moderate watering is the key.

Any check to growth, caused for example by a couple of days of drought, can be damaging or even fatal to mustard plants.

For that reason, too, they need to be grown in rich, moisture-retentive soil. Trying to squeeze them into a patch of dry, dusty ground would be a waste of seeds and time.

In case you’re new to growing oriental greens, here are two types that I’ve found among the most trouble-free and useful.

Mizuna produces large numbers of dark, serrated leaves and grows in clumps which can be cut and left to regrow several times over a period of months. 

It is tolerant of both high and low temperatures, a vigorous grower and good in salads and stir-fries. The taste is mildly mustardy.

Oriental Saladini is a seed mix of several oriental vegetables, which can be used to create a patch of cut-and-come-again leaves for salad and cooked dishes. 

An autumn sowing, protected against frost, will provide greens through winter and into early spring.