Frost monitoring and protection

September 2007 | Craig Hornblow, AgFirst | Future Orchards® Orchard Walk notes

These notes explain how frost risk changes through the spring growth stages and outline practical measures growers can use to monitor conditions and protect vulnerable apple and pear blocks. As buds move from dormancy through green tip, pink, bloom and post-bloom, the temperatures capable of causing damage become progressively less extreme.

The resource stresses the importance of local monitoring rather than relying only on district forecasts. Orchard topography, cold-air drainage, wind, humidity and inversion strength all influence actual block temperature. Understanding where the coldest parts of an orchard are located helps growers position sensors and decide where protection systems will deliver the most value.

Protection options include orchard-floor preparation, wind machines and water application. The Future Orchards® program notes that frost-protection systems must be matched to the type of frost and local conditions: wind machines depend on a useful inversion layer, while sprinkler systems need reliable water supply and sufficient application rate.