Keeping avocado trees cool when the heat is on

Extreme heat events are becoming an increasingly common challenge for Riverland growers, putting crop health, fruit quality and productivity at risk. 

During the 2025-26 season, Renmark experienced exceptionally hot conditions, including a record maximum temperature of 49.6°C. As temperatures climb, so does the risk of heat stress for irrigated horticulture crops.

To help growers adapt the Murraylands and Riverland Landscape Board’s Climate Smart Agriculture project is working with local growers to demonstrate cooling irrigation and integrated monitoring technologies in crops including avocados and table grapes.

By lowering canopy temperatures, cooling systems can help reduce heat damage to leaves and fruit, improve conditions within the orchard canopy and support continued plant function during extreme weather.  

Cooling an avocado canopy

One of the project’s demonstration sites in Renmark is exploring how overhead cooling irrigation can help moderate canopy temperatures during hot conditions. 

Data recorded on 25 January 2026 shows how quickly the avocado canopy responded when cooling irrigation was activated, with monitoring at multiple heights providing insight into temperature changes throughout the canopy.

Following a high overnight temperature and rapid temperature increase, a short cooling irrigation pulse was started at 10:30 am as temperatures reached 31.5°C, by 11:30 am the canopy temperature had dropped to 25.5°C when the system was switched off. 

At 2:30 pm, canopy temperatures had climbed to almost 38°C. Once the cooling system was turned on, temperatures began falling rapidly despite air temperatures continuing to rise.

After 90 minutes of operation, canopy temperatures had dropped to 33°C. After 2 hours, they had fallen by more than 6°C to 31.7°C even as the day’s maximum temperature reached 46°C.

The results provide a practical demonstration of how cooling irrigation can help reduce canopy temperatures during extreme heat events, potentially lowering the risk of heat-related damage to trees and fruit. 

What’s next?

The next phase of the project will investigate how the cooling system can be further optimised.

This includes identifying opportunities to improve cooling performance, increase water-use efficiency and refine the temperature trigger points that determine when the cooling system starts and stops. By matching cooling more closely to plant needs, growers may be able to achieve better outcomes while using water more efficiently. 

This project, is supported by the Australian Government through funding from the Natural Heritage Trust under the Climate Smart Agriculture Program.