Farm of the week: Salad days are never ove rat the tastiest enterprise

In fact, Herbs Unlimited did start out as a gardener's pin-money hobby. But it has grown into something surprisingly big for a business dealing in very small parts of the average meal. It has four acres devoted to parsley, for example – which seems a lot if you don't know it as a standard ingredient of soups, sausages, stocks and sauces.

Alison Dodd, who started the business with a spade 17 years ago, oversees a workforce which grows from 25 to 35 in the summer, turning over 2.2m and delivering an average of nine tonnes of salads and herbs a week.

Her three children were at school when she took on four acres to start growing for local restaurants. Way back in 1992, it had become more or less impossible to buy fresh thyme or chives, she said and dried and packed versions had taken over.

But Mrs Dodd had run a restaurant – still going as The George, at Wath, near Ripon – and knew chefs still knew the difference a fresh leaf could make. So she set to work with the only manual she could find, a paperback copy of Growing Herbs, by Rosemary Titterington.

Her customers started to ask for mixed baby salads too and she did well out of knowing what they wanted. Some mixes sold by supermarkets are "just horrible", she says.

Her standard mix includes Ameranth, Baby Spinach, Black Cabbage, Bulls Blood, Chicory Italiko, Chop Suey Greens, Greek Cress, Mizuna, Red Chard, Red Mustard, Red Perilla, Red Russian Kale and Rocket.

She learned her first rule of business: "Never say you haven't got it." That meant becoming an importer in winter and a French relative directed her to the Rungis market, in Paris, where fresh Israeli produce came in all year. Covent Garden has since cottoned on but Mrs Dodd had by then built her own supply network.

One turning point was when sausage-maker Cranswick, making an upmarket range called Lazenby's, in Hull, commissioned a recipe from Le Gavroche and came to her for the fresh seasoning the Roux brothers insisted on. More recently, she has an order from a soup-maker who has turned from frozen to fresh spinach.

"With salt becoming taboo, the food processors have to find replacement flavours," she said.

Her latest challenge is to provide a hard-to-grow herb called Perilla, with an aniseedy flavour, for a drinks company at Leeming which deals with Japan, where they like it in drinks and on sushi.

She has two daughters grown and flown. Her son, Philip, went to Harper Adams College, worked for a grower in Kent and came back to become her farm manager. They use biological pest controls where possible – ladybirds on leafhoppers in the polytunnels, for example. But it would be hard to be fully organic and their biggest recent problem has been an EU ban on the pre-emergence weedkiller Prophaclor (boxed as Ramrod). It means a lot of hand-weeding and Mr Dodd, 29, is worried about other bans due by 2013. The danger from last year's controversial zero-risk legislation is far from over, he says.

Mrs Dodd, 59, is managing director while her husband, David, is retired. She is mainly an administrator, nowadays, but keeps an eye on her specialist corner where she grows nasturtiums, marigolds, pansies, cornflowers and other offbeat edibles, for the odd culinary artist who wants them.

Three factors have worked in her favour – celebrity chefs, the food miles issue and the burgeoning of food safety rules. She has taken each on as it came up but altogether they are a daunting obstacle to copycats. It costs 2,000 a year just for the chemical residues tests for her current crops.

There has, however, been some bad luck too.

When the business was taking off, the gardens at Northallerton Prison came up for rent. The contraction of the prison farms network is now lamented but at the time, it suited Mrs Dodd very well. After four years, however, the Home Office took the land back to sell for housing.

She was saved by a deal with Trevor Bosomworth, who lost his livestock in the foot and mouth year and was looking for a new direction. In 2002, with some Defra subsidy for diversification, they built polytunnels on his land at Sandhutton, just outside Thirsk.

Local mutterings about the polytunnels came first. In February 2006, a clearly calculated arson attack took out several key pieces of plant. Nobody was ever caught and the unease lingers.

"We only lost a day's production but it took two years to fully recover," says Mrs Dodd. "I thank God I took my laptop home that night, so at least I had my phonebook to work from."

It is hard to see what made someone so vicious. The polytunnels are hidden up a lane and animal manures are out, because so much produce goes for raw consumption.

But in deference to sensitivities, the farm has expanded mainly at ground level. It now covers about 60 acres, including two under plastic. Indoor plants come earlier and softer. Outdoor crops are slightly less valuable.

The business now has a range of markets. The restaurant trade, from Glasgow down into Notts, takes most of the best produce. Booths of Ripon buys some and the farm contributes to Sainsburys' British Herb Season through dealers. Big merchants take some of the field crops raw, but the farm also has its own packing shed.

Today it is preparing chives for the dealers' market in Manchester. Farm shops also take some packed and branded produce.

Most harvesting staff are Rumanian students while most permanent staff are local. In the interests of keeping them occupied all year, the farm has started to pot seedlings for garden centres. Another new venture is a partnership – www. herbfed.co.uk – with a nephew, Edward Wilkinson of Sessay, who is feeding surplus crops to his turkeys.

The business website: www.herbsunlimited.co.uk

HOW TO GET GROWING

For a beginner's herb garden, Alison Dodd recommends...

Rosemary: "The easiest way to get complimented on your cooking is to stick a few sprigs under a piece of lamb. Try Miss Jessop's."

Mint: "People are frightened of it taking over, but the secret is to keep cutting it right back and making it come again. Moroccan stands up better than English."

Thyme and chives: "Just the common varieties."