Genevieve Roberts joins the latest food craze and goes foraging

Scores of boxes line forager Miles Irving's order room, the names scribbled on them forming a rollcall of top London restaurants: The Ivy; J Sheekey; Marcus Wareing; The Ledbury; Le Caprice; Roganic; Pollen Street Social; Hix Soho. Each is marked with orders for foraged goods – chickweed and sea aster, wild chervil and sea purslane – picked from the Kent countryside.

Today, the author of The Forager Handbook is hoping to gain a new client, Ashley Palmer-Watts, head chef at Heston Blumenthal's restaurant, Dinner.

Once seen as a hippie eccentricity, foraged food has boomed in popularity. Noma, in Copenhagen, named the world's best restaurant, serves ingredients from forests surrounding the Danish capital. In the UK, many of the best restaurants order foraged goods, or, in the case of Sat Bains's restaurant in Nottingham – which has a dish named after the postcode from where the ingredients were foraged – or David Everitt-Matthias's Le Champignon Sauvage in Cheltenham, the chefs pick their own. Online maps show foraging enthusiasts where to find the best wild fruit and berries.

Irving, 43, started his business in 2003, supplying restaurants with wild goods, but he first went foraging for mushrooms with his grandfather when he was six, learning about parasols and puffballs. He now knows more than 400 plants – the majority of them included in his book – growing wild.

He believes foraged food has huge implications for the future. "Salads thrive if you mow your lawn less often – and there are a lot of lawns about. If there are fears about feeding future populations, then better land use would mean we'd have no problem feeding nine billion."

We start our foraging along the riverbank in Chartham, near Canterbury in Kent.

Irving starts me off with the basics. Nettles. They're good for soup or pesto, and are the easiest plant to forage. "It involves no skills, just hands that aren't totally sensitive to pain," he says. They taste peppery, more nutty when cooked.

The greater plantain, with flowering spikes like mini asparagus, tastes of mushroom, while sour thistle has the bitterness of cooked chicory. Wild sorrel is like strong lemon, while wild rocket is spicier than any I've bought in supermarkets.

I nibble wild chervil, and Irving gives a warning to wannabe foragers. "This looks very similar to the hemlock, which will kill you," he says. "The only difference is smell, and little purple spots on the hemlock stem." We squeeze pulp from rosehips, and Irving shows me wood avens, a spice that tastes like cloves.

With the ingredients we've picked, and a "here's one we prepared earlier" box, we head to Dinner in west London. Irving is excited about supplying Heston Blumenthal's latest venture. "Many people celebrate our ingredients by doing as little with them as possible, which is great. But it will also be good to see that scientific approach flesh out their potential," he says.

Ashley Palmer-Watts is impressed. He munches through leaves tasting of pepper and horseradish, lemon and coriander, many of which he's never previously heard of or seen. I've been warned that no chef decides immediately to place an order, but this is not the case. "We'll get an order in next week," Palmer-Watts says.

And Irving will have another box to fill.

Fodder facts

Foragers are concerned about the scarcity of white truffles, most famously found in Alba, northern Italy, this autumn. Truffle season has been delayed because the weather's been too warm for these "diamonds of the kitchen". Heinz Beck, of Michelin-starred restaurant Apsleys at London's five-star Lanesborough hotel, said: "This is the first time in the past 17 years I have seen truffle season start so late."

In Britain, leaves and herbs are plentiful now. Autumn foraging favourites include chickweed, which tastes like spinach; wild sorrel, tasting of lemon, found in grassy areas and riverbanks; nettles; sloes, found in hedgerows, used to make jelly and gin; sea arrowgrass, found in salt marshes; watercress, also called watercelery, found alongside rivers and streams, tasting of celery.

Genevieve Roberts