Heat stress is one of the most significant and increasingly common challenges for production nurseries and retail garden centres in NSW and ACT. Higher summer temperatures, longer heat events and more frequent extreme days affect plant quality, labour productivity and operational costs. Effective heat management is a core capability for maintaining stock consistency, protecting staff and achieving reliable plant performance.
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Understand the Conditions Driving Heat Stress
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Root zone temperature is often the hidden factor. In black containers, media can exceed ambient air temperature by 10 to 20 degrees, directly affecting nutrient uptake and growth. Australian university research consistently shows that reducing root zone temperature improves performance and reduces losses.
Shade Design that Works
The most effective shade strategies consider both percentage and placement.
Shade Cloth Selection:
Balancing protection without restricting growth is essential.
Shade Structure Orientation:
East–west orientation reduces morning and afternoon heat intensity. Ensure ventilation along the sides and at the roof apex to allow heat to escape.
Movable Shade Systems:
Retractable or adjustable shade systems help nurseries respond quickly to extreme temperature spikes. Studies show they improve summer uniformity and reduce losses.
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Water Management and Irrigation Adjustments Short, frequent cycles help maintain moisture in the upper root zone without creating waterlogging. Timing: Early morning irrigation reduces stress before peak heat. In extended heat events, a light afternoon cycle may be required to stabilise plants. |
Monitoring pH and EC:
Heat influences nutrient uptake, so regular monitoring prevents deficiencies and imbalances. This aligns with recommendations from NSW DPIRD and university agronomy programs.
Air Movement and Ventilation
Increasing airflow lowers leaf temperature and improves evaporative cooling. Options include:
Even moderate airflow can significantly reduce heat load during extreme days.
Root Zone Protection
Protecting the root zone is essential for resilience. Strategies include:
These adjustments reduce heat accumulation and support stronger root development.
Staff Safety and Workflow Adjustments
Heat stress management must include worker safety. Best practice includes:
These steps align with SafeWork NSW guidance for outdoor workplaces.
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Emergency Response During Heatwaves When temperatures exceed thresholds or forecast conditions change rapidly, activate a clear response plan:
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Documenting this plan ensures consistency and reduces losses.
Why Proactive Heat Management Matters
Proactive heat strategies support:
Industry research consistently links environmental control to improved margins, demonstrating that heat management is both a horticultural and business priority.