Mark has a very gentle
touch that makes him the right choice for protecting tender spring
growth from late freezes. He wrapped both young grapevines in front of
our trailer in preparation for the cold spell, covering up all of the
stems that have flower buds attached. Fingers crossed the plants inside
those bundles will make it through Blackberry Winter unscathed.
Ontario gets a lot of frost in the spring, can be a real problem for tender fruit production. I grew up on a tender fruit farm, smudge was one of the techniques used, but I also remember the sprinkler system being used. Anyway, here is an Ontario farm viewpoint on frost and frost protection.
http://www.omafra.gov.on.ca/english/crops/facts/85-116.htm