Grower, Andrew Johnson was selling an average 10,000 trays of his Home Harvest baby-leaf salad each week over the summer. His customers include Sainsbury's supermarket, as well as some of the larger regional outlets.

Having developed the idea with help from researchers at Stockbridge Technology Centre, N Yorks, Mr Johnson will soon be moving his business to a rented nursery site near Hull.

The idea for the 'living salad' came when he was living in Portugal, and had adopted the habit of picking fresh salad leaves straight from the field. "Consumers are already used to buying growing herbs in pots, so I thought I would test the market with a similar concept for salads," explains Mr Johnson, who was a recent BBC Food and Farming Awards finalist.

"My previous experience as a production director supplying vegetables to supermarket buyers came in useful, and I already had some good contacts. With a low-value product, I needed to get the larger stores involved to move enough volume to make a margin."

Securing a supermarket contract was the start of a steep learning curve, he admits. "Consumers have to be persuaded to get into the habit of choosing your product, and that can be difficult, especially if you are offering something new. High-quality labelling and packaging is very important – it's no good cutting corners on design costs.

"The producer has virtually no control over transport charges, and they can be much higher than you might imagine. In the winter, when people buy less salad, distribution costs per unit are very high, and can have an enormous impact on annual profitability," says Mr Johnson. He suggests seeking advice from a specialist food retail expert.

"I employ a 'poacher turned gamekeeper', which has made life much easier. I was lucky enough to find a female consultant who was taking a break from a high-powered retail job after having a baby. I would never have been able to afford to employ her full-time, but the flexible hours I was looking for suit both of us," he adds.