LONDON - Britons struggling to get hold of tomatoes, peppers and cucumbers as the nation faces a shortage that could last for another month might consider turnips instead, the minister in charge of the country's food supply said on Thursday.

On Wednesday, Britain's biggest supermarket group Tesco followed rivals Asda, Morrisons and Aldi in imposing customer purchase limits on salad after disrupted harvests in southern Europe and north Africa reduced supplies.

The shortage has been exacerbated as high energy costs has led to less winter production in greenhouses in Britain and the Netherlands.

Therese Coffey, minister for the environment, food and rural affairs, said Britons could eat more seasonally, although she was conscious consumers had become used to supermarkets ensuring year-round availability of almost all produce.

"It's important to make sure that we cherish the specialisms that we have in this country," she told parliament.

"A lot of people would be eating turnips right now, rather than thinking necessarily about ... lettuce and tomatoes," she said, referring to the root vegetable traditionally available in Britain at this time of year.

She said the shortages could last up to a month.

"I'm led to believe by my officials after discussion with industry retailers...the situation will last about another two to four weeks. It's important that we try and make sure that we get alternative sourcing options," she said.

(Reporting by James Davey and Kylie MacLellan; editing by William James and Barbara Lewis)