Definition of Terms
Cold hardiness is the ability to resist injury during exposure to low temperature.
Cold tenderness is the opposite of cold hardiness.
Cold injury is the killing by low temperature of some part of the vine.
Seriousness of cold injury is indicated by the amount of decrease in fruit production and/or quality resulting from cold injury.
Dehardening is the process after the chilling requirement (rest) is satisfied whereby the plant or tissue loses hardiness and is ready to resume growth.
Dormancy is the condition of a bud or seed characterized by the lack of outwardly visible growth.
Double pruning is the cultural practice whereby twice the number of buds dictated by the balanced pruning formula are retained after an initial pruning in early to mid winter. A second pruning is done after bud damage can be assessed and/or the threat of spring frost injury is minimal.
Hardening is the process by which a plant or tissue is made more resistant to any environmental extreme such as low temperature.
Rest is a state of suspended growth due to internal physiological blocks. Rest is fulfilled by exposure to temperatures of 45°F (7°C) or less for an extended period (chilling requirement). After the rest period is satisfied, a plant may either break dormancy and begin to grow if conditions allow, or may remain dormant if conditions do not favor growth.