View by Author:
View Blogs:
Managing Heat Stress in Greenhouse Crops and Employees
As summer temperatures soar, heat stress becomes a critical concern inside greenhouses, affecting both crops and employees. Greenhouse environments can quickly exceed outdoor temperatures, especially during midday, creating challenging conditions for plant growth and worker safety.
For crops, heat stress can interfere with normal plant growth and development, leading to symptoms such as stunted plant growth, leaf curling and scorch, leaf and flower abortion, flower color discoloration or fading, and plant wilting. Prolonged high temperatures can also make plants more susceptible to pests and diseases, compounding production challenges during the peak of summer. To mitigate these risks, growers should focus on increasing air movement by operating horizontal airflow fans, opening vents, and using exhaust fans to expel accumulated heat. It is also important to closely monitor irrigation, adjusting schedules to maintain consistent and uniform soil moisture. Avoid both over-saturating the substrate and underwatering. If intentional water stress is being used as a growth control method, plants should be checked frequently to prevent reaching the permanent wilting point, which can cause severe damage and plant loss. Watering early in the morning ensures plants are well-hydrated before the hottest part of the day. During periods of extreme heat, reducing light intensity with exterior-applied shade compounds, shade cloths, or deploying retractable screens can help protect sensitive crops. Additionally, placing high-light and heat-sensitive crops in the coolest greenhouse zones may offer added relief.
Employee safety is equally important, as greenhouse workers are at significant risk for heat-related illnesses such as heat stress, heat exhaustion, and heat stroke. Heat stress occurs when the body’s temperature rises due to exertion or a warm working environment, and even a small increase in body temperature can impair mental functioning, while more severe increases may lead to serious illness. Individuals with pre-existing health conditions are at even greater risk. Symptoms like dizziness, fatigue, confusion, and muscle cramps can develop quickly, so it is essential to provide easy access to cool drinking water, encourage frequent breaks in shaded or cooler areas, and adjust work schedules to avoid the hottest parts of the day when possible. Training employees to recognize early signs of heat stress, implementing a buddy system, and promoting gradual acclimatization to hot conditions are effective strategies. Additionally, lightweight, breathable clothing can further reduce risk. Early recognition of symptoms and prompt response are critical when workers are suffering from heat stress. Maintaining awareness and taking proactive steps can help ensure a safer and healthier work environment during the hottest months of the year.
By prioritizing both crop and employee heat stress management, greenhouse operations can maintain productivity and ensure a safer, more successful summer season.
About the Author:
W. Garrett Owen is an Assistant Professor of Sustainable Greenhouse and Nursery Systems in the Department of Horticulture and Crop Science at The Ohio State University. He has an appointment in research, teaching and Extension. His area of expertise is plant nutrition; plant growth regulation; and production problem diagnostics.
W. Garrett Owen
Assistant Professor of Sustainable Greenhouse and Nursery Systems, The Ohio State UniversityW. Garrett Owen is an Assistant Professor of Sustainable Greenhouse and Nursery Systems in the Department of Horticulture and Crop Science at The Ohio State University. He has an appointment in research, teaching and Extension. His area of expertise is plant nutrition; plant growth regulation; and production problem diagnostics.