What factor should be monitored during winter pruning to avoid frost damage?

Monitoring temperature and the likelihood of frost during winter pruning is crucial to prevent frost damage to grapevines. When pruning, growers remove a significant amount of plant material, which can expose fresh cuts and sap to the elements. If temperatures drop significantly after pruning and frost occurs, the newly exposed tissues can suffer from freeze damage, leading to potential loss of buds or compromised plant health.

By paying attention to forecasted temperatures and frost risks, vineyard managers can time their pruning to coincide with periods of milder weather. This practice helps to ensure that the plants can heal from the pruning cuts without being damaged by adverse cold conditions.