Farmers are "increasingly concerned" about fruit and vegetable crops after the driest winter in 20 years
Most rivers across England have been at lower levels than usual, and less than half the average amount of rain fell in the UK in April.
Some rivers have run dry in Cumbria, with reservoir levels in Cornwall dwindling.
BBC weather said April had been especially dry, seeing only 47% of the average rainfall across the UK.
However, some wetter weather is expected this weekend.
National Farmers' Union vice president Guy Smith said some farmers, especially those in the south and east, had reported as low as 10% of the expected rainfall for March and April.
"While decent rains in May and June will put many crops back on track, some crops like spring barley have clearly already lost their full potential," he said.
"Some farmers and growers are looking at the 'changeable' forecast for the end of this week hoping it brings much needed rain.
"We are growing increasingly concerned about the fruit and vegetable sector, but reservoirs are full and abstracted water sources are still available, albeit at lower that normal levels."