What is a leek doing in West Sussex? I ask only because growing them requires such a lot of faffing around that they cannot possibly be native. You have to dig them up, trim them, make deep holes elsewhere, drop them in, water the hole – and leave them looking rather bedraggled.

Sarah Wain (see below) tells me this is essential and I am not allowed just to leave them in the seed bed; they need to be replanted deeper. That made me wonder how we came to grow such a thing in the UK – and how did a foreign vegetable come to be an emblem of Wales?

It seems the leek hails from Asia and the Mediterranean, even turning up in Ancient Egyptian tomb paintings. The Book of Numbers records how, after leaving Egypt, the children of Israel missed a range of foods, including leeks. The others? Fish, “which we did eat in Egypt freely”, cucumbers, melons, onions and garlic. All they were left with was manna.

One of the Hebrew words for leek, karti, is a pun on another word that means “to be cut off”, hence it is eaten by some Jews at Rosh Hashanah to symbolise their wish for something dreadful to happen to their enemies – a stark piece of symbolism.

But what is it doing in my garden? Phoenicians trading for tin are thought to have introduced the leek to Wales. One and a half millennia later, legend has it that King Cadwaladr ordered his soldiers to identify themselves by wearing a leek on their helmets in a battle against the Saxons. Cadwaladr’s men won, hence the leek’s status in Wales.

And here’s how you grow it.

Sarah Wain’s expert advice

The long white stem is achieved by excluding light. If you leave the leeks in the seed bed then you get spring onion-like vegetables: they are delicious harvested pencil-thick, steamed and dressed with vinaigrette. But to grow big leeks you need to lift the seedlings when they are 8-10in high, lightly snip off the end of the roots and tops and place them in dibbed holes about 5-6in deep, 6in apart, at the bottom of a 3in-deep trench. It’s important that the roots of the leek do not bend back upwards. You can make all measurements shallower if your soil is clay-based.

Use a watering can to water in the leeks. Do not fill in the holes; this needs to happen naturally to allow the leek to grow.

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