Pembrokeshire farmers are to be encouraged to grow new vegetable varieties after rising to the challenge of satisfying all the potato sales needs of their main buyer.

All the potatoes sold in the Welsh stores of supermarket giant, Asda, are now supplied by the Haverfordwest-based growers' co-operative, Puffin Produce.

Its members had previously been growing eight varieties of potato, but to meet Asda's all-the-year round supply it needs to add a further three. Puffin growers now supply Asda with 16,000 tonnes of potatoes annually.

This season 70 acres of Savoy cabbages and spring green are being grown for the first time alongside crops of cauliflowers.

Martin Cocks, managing director of Puffin Produce, said the co-operative was now looking to expand that range.

"There are still opportunities for other products and over the next few months we will be looking at the viable options on some other lines which Welsh consumers would enjoy."

Until last year, Puffin had been supplying Tesco, but switched to Asda because it believed it offered more opportunities for its growers.

Reflecting on the end of its first full season with Asda, Martin Cocks said the new contract had provided growers with the confidence to reinvest and to rent more land.

"Most of our suppliers are taking the opportunity to increase their acreage," he said.

"Asda wants its growers to build a sustainable and viable future and this is the reason why it offers returns which put them in a position to invest and plan for the future."

Apart from one grower in Usk, who supplies Puffin with 30% of its white potato needs, potatoes sold through Asda's Welsh stores are all grown in Pembrokeshire.

The supply needs of Asda have also enabled growers to rotate crops to get the best from their land, said Martin Cocks. "Around the coast of Pembrokeshire there is a block of land which will grow early potatoes well.

This block is now becoming tired. We are now in a position to get the right rotation in place."

The new cold store at Puffin's Withybush site has been central to its expansion into new varieties.

Each variety requires a different storage regime and with three bays, each with a 1,000 tonne capacity, potatoes can be stored under their required conditions.

"Each will be controlled at a different temperature to prolong the quality and the life of those particular varieties," said managing director, Martin Cocks.