Does extreme cold damage vines in their dormant phase…?
Yes, extreme cold temperatures can injure grapevines – buds can even freeze.
Across Europe and the US this year we have again seen severe weather conditions that will have an effect on the wine harvest this year.
The temperature at which this happens varies according to the grape variety and the time during dormancy.
During damaging temperatures, growers slice open buds to see what percentage are dead.
If more than 20% bud death is noted, growers adjust their pruning by leaving more buds to compensate.
This works as growers typically prune off 90% of dormant buds.
Other ways growers cope is to have several trunks on each vine (they renew trunks every few years) or by mounding up dirt over the graft union (‘hilling-up’) to protect scion buds so they can train up new trunks.