Farmers in the east of England have said they face huge losses as the extreme cold weather has made it impossible to harvest their root crops.
The ground is frozen so hard farmers in Norfolk, Suffolk and Cambridgeshire cannot lift their parsnips and carrots.
Kevin Hammond of Syderstone in Norfolk said according to farm diaries it was the worst weather for 35 years.
One firm said 200 acres of its carrots, which are more vulnerable to frost than parsnips, were at risk in Suffolk.
Ian Hall, manager of Tompsett and Burgess, based at Isleham in Cambridgeshire, said had seen its capacity reduced by 20%.
Parsnips can withstand extreme cold but carrots are more vulnerable and a hard frost can destroy them, the growers said.
Mr Hammond said: "We would normally be putting through 125 tonnes a day of parsnips and 40 tonnes of carrots. Today we have lifted and processed 20 tonnes of carrots and no parsnips.
"At the moment I have 60 acres at risk and if you take an average cost of £1,200 an acre to grow that gives you an idea of the cost implications that we're facing."
Mr Hall said growers usually laid straw over some parsnip and carrot crops during the winter to stop the frost penetrating the ground so that harvesting could still go ahead.
But he said even though the ground was starting to "give a little" on Wednesday the layer of straw had no effect earlier in the week.
Mr Hall said: "Normally there's a hard frost in January but this year it began at the end of November."