(Bloomberg) -- European potato prices are soaring as heavy rains leave spuds mired in the mud, curbing supplies just as demand for the Christmas-dinner staple rises. 

Farmers in Belgium, France and the UK have sidelined tractors, which have difficulty navigating waterlogged fields, limiting collection. The crops risk rotting if left too long. Potato futures in Europe are now trading at the highest seasonal level in at least 14 years. 

“It has pretty much just rained and rained,” said David Mitchell, director at supplier Mitchell Potatoes Ltd., near Rugby in central England. A cold snap last week also froze spuds in the ground after months of the land being “very sticky,” he said.

The surge in potato prices is the latest example of a growing number of crops affected by climate change. Futures for the commodity, although thinly traded, spiked in May due to heavy rains. Wet weather has also risked wiping out part of the continent’s sugar beet harvest and has delayed winter grain plantings in France.

Most potatoes are harvested by late autumn, but around 15% of the Dutch crop remained in the ground in November, according to the North-Western European Potato Growers foundation. The Netherlands was the continent’s fourth-largest producer in 2022, after Germany, France and Poland.

Shortages are also hitting packing potatoes, the varieties sold in smaller quantities to consumers in supermarkets. It’s driving a “flurry of activity,” said Harry Campbell, a fruit and vegetable analyst at Mintec. “A lot of pack houses are trying to secure their Christmas stocks now.”

That risks adding to the costs of meals during the festive season.

The wholesale prices of Maris Piper potatoes — a fluffy, white, versatile variety used for baked potatoes, fries and roasting — show the squeeze. Last week prices were up 158% on the year, at £465 per metric ton, according to Mintec.

Elevated wholesale prices have been feeding through to consumers. In France, annual inflation for potatoes was at 19% in October, the latest available data, while overall inflation was at 4.5% that month. 

With supply security precarious, farmers are reserving crops to meet pre-arranged contracts rather than enter into the more volatile spot market, according to Campbell.

But pain from the delay in harvesting is expected to weigh on supplies into the new year. “Even if you get them out before they’ve completely rotted, you aren’t able to store them for long periods of time,” he said. 

©2023 Bloomberg L.P.