Greenhouse cooling techniques

Maintaining optimal temperature is critical for plant growth, flowering, and fruiting. Cooling is especially necessary in hot and semi-arid regions to prevent heat stress.

A. Ventilation

a. Natural Ventilation

  • Roof and side vents allow hot air to escape and fresh air to enter.
  • Cross-ventilation ensures uniform temperature and humidity.

 

b. Forced Ventilation

  • Use of exhaust fans to remove excess heat.
  • Fans maintain air movement and prevent hot air pockets.

 

B. Shading

a. Shade Nets

  • Reduce solar radiation by 30–70% depending on crop requirements.
  • Protects plants from leaf scorching and overheating.

 

b. Whitewash / Shade Paint: Applied on greenhouse covering to reflect sunlight and lower temperature.

 

C. Evaporative Cooling

a. Misting or Fogging Systems: Fine mist evaporates around plants, reducing air temperature and increasing humidity.

 

b. Wet Pad System (Pad and Fan Cooling)

  • Air passes through water-soaked pads; evaporation cools incoming air.
  • Common in commercial greenhouses in hot climates.

 

D. Thermal Screens

  • Retractable screens or blackout curtains reduce heat gain during daytime.
  • Can also retain cooler air in shaded sections of the greenhouse.

 

E. Roof and Side Design

a. High Roof & Sloped Roof: Promotes hot air escape naturally.

b. Proper Orientation: Aligning greenhouse to optimize airflow can enhance passive cooling.

 

F. Automation and Sensors

  • Temperature Sensors detect excessive heat.
  • Automated Vent or Fan Control ensures timely cooling without human intervention.
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