Unseasonably cold nights were experienced across much of the UK last week, with frosts hitting the south of England and snow falling further north and into Scotland.
Hutchinsons agronomist, David Stead, who is based in North Yorkshire, says it is one of the harshest May frosts he has seen in his 10 years as an agronomist. He expects some of the worst hit potato crops might see a small yield penalty.
“The earliest planted crops which were nicely up at rosette stage have had some damage and the outer leaves have been fairly badly crisped up. Luckily a lot is still under fleece which has kept them protected.”
The focus now will be to keep crops as healthy as possible and keep blight out of any wounds caused by the frost he says.
“Manganese and zinc are particular micronutrients that we will be putting on to help compensate for the damage done.”
The dry spring being experienced across much of the UK is also causing difficulties, Mr Stead adds.
“I have got customers irrigating crops before they have even emerged – in my area we have had around 20mm since March 20. The frost on top of that is another extreme.
“The dry weather is also making weed control quite difficult as well because we rely on residual herbicides.”
Disease-wise the cool weather has kept pressure low although a Hutton Criteria has been forecast for this Wednesday into Thursday, he says.
Crops further south have also been hit. Shropshire-based Geoffrey Bastard, technical specialist at Certis, says the frost could set back some early potato crops with larger haulms but potato crops that were irrigated the night before have mostly been able to escape the worst of the damage.
The most likely scenario is crops will be set back a few weeks which can harm yield expectations, Mr Bastard says.
“I doubt the freeze was severe enough to cause actual seed tuber damage, unless seed was exposed by eroded ridges or poor planting.
“Stressed plants will have been at greater risk of damage and this can be difficult to manage when it has mostly been quite dry since planting, and soil may not have been in the best condition following winter waterlogging or floods.”
Adequate crop nutrition will be key to managing this and getting a healthy crop back on track, he adds.
“Naturally a stressed or sick crop is more at risk of disease, though the low temperatures themselves may also have hindered disease development.”