Sidewood keeping ‘Jack Frost’ at bay
Early spring frosts have struck the Adelaide Hills and Barossa Valley in recent weeks, and some vineyards are better prepared than others. Adelaide Hills vineyard Sidewood claims its Mappinga Road vineyard at Woodside has the biggest vineyard sprinkler frost control system in the southern hemisphere.
Proprietor Owen Inglis sent me these graphic pictures of the effect of sprinkler frost control at Mappinga Road.
The principle is simple, but at first seems counter-intuitive. When the air temperature at bud level falls to 1 degree Celsius, pumps switch on and above-vine sprinklers distribute water. The water mist freezes when it hits the vines, forming a shield of ice, which encapsulates all parts of the vine including the buds. It seems unlikely, but the temperature inside the ice capsule is higher than outside, so the delicate fresh green growth just emerging out of the buds is protected from being burnt. The ice, of course, melts later in the day, and by then the ambient temperature is up to a safe level.
The critical period for damage to vines is in the first two or three weeks after budburst, as the fresh growth is very delicate and prone to burning.
Sprinkler technology is widely used in Coonawarra but less so in the Adelaide Hills and little in the Barossa.
Owen Inglis says his Mappinga Road vineyard had experienced seven frost events so far this spring, when I contacted him on October 12. He said this included an unprecedented six frosts in seven nights. His vineyards in warmer sites were hardly affected, but one of his smaller vineyards was 90% affected.
“The frost system goes off automatically at 1 deg C and sends alarm notifications to Mark Vella (chief viticulturist) and three others. It sets off two main Cummings engines that put out 400 horsepower each, activates 50,000 flippers and we get through up to 1 megalitre per hour (equivalent to one Olympic swimming pool).
“It is sectioned so that if part of the vineyard is not below 1 deg C we don’t waste water. Most of the water flows back into the dams and the water table.
“We have never experienced 6 days out of 7 before. Interesting start to the season.”
When the alarm goes off, vineyard workers spring out of bed and hurry to the vineyard to make sure the system is working properly.
“Have to feel sorry for the two viti guys on duty. They rush out to the vineyard in their full Musto and patrol the vineyards on quad bikes for the entire duration of the event, looking for any flippers that are damaged or blocked, and repairing them as required.
“They may as well be standing in a shower.
“Temperature was recorded by them as down to -4.3C in the lowest sections of the vineyard.
“I’m sure they were cursing Sidewood, Bacchus and everyone in between by the end of it all.”