Harsh frosts could cost 1000 tonnes of grapes

The unpredictable nature of frost has been demonstrated as some Central Otago vineyards suffered extensive vine damage when the temperature plummeted while others remained untouched.

Central Otago Winegrowers Association president James Dicey estimated 1000 tonnes of grapes had been lost, though "we won't know for sure until mid-December".

The damage had been spread around Central Otago, he said.

"There are some people who have lost 60%-70% of their crop and there's people who have lost virtually nothing."

He would not make a diagnosis of which vineyards would not recover, since he had seen "miraculous recoveries" of damaged vines.

He said pinot noir was worth $3100 per tonne and if the estimate of 1000 tonnes of lost crops was correct, the total loss could be over $3 million.

Despite the damage, Mr Dicey stressed "this is going to affect quantity, not quality".

Peregrine Winery brand ambassador Greg Hay said his vineyards, spread across Central Otago, did not appear to have suffered as much as others.

"I've had a couple of friends who have said they have been hit badly," Mr Hay said.

While "no frost is ideal", if it had struck in three weeks' time, the vines "would never recover", Mr Hay said.

"No frost would be classified as good, but if you were to get these leaves burnt early in the season, the vines do have a chance."

"I'm sure within Central Otago there is varying degrees of damage. The last time we had a frost like this was 2004."

Mr Dicey said there were a series of alarms to alert growers to potentially damaging temperatures and he worked through the night to mitigate damage.

Frost machines and helicopters were used to mix hot air with lower colder air, though sometimes it was a gamble whether these measures could beat the weather.

Fruitgrowers in the Roxburgh area have also had busy nights, with four frost alarms since Labour Weekend.

Fruitgrower Stephen Jeffery, of Roxburgh, said it was not unusual to have one or two frosts at this time of year but four, with more forecast, was unexpected.

He said the frosts were relatively mild and he expected fruitgrowers using overhead sprinklers would have been well prepared.