Air temperature sensors should be shielded from direct sunlight and aspirated. Sensors exposed to sunlight will over estimate air temperature.
Sensors should be inside units that are painted white or other reflective color and use a small fan (arrow) to aspirate or move air across the sensor to provide a better greenhouse air sample.
Air temperature sensors are connected to computerized environmental control systems that operate heating units, fans, thermal curtains, and vents.
Temperature sensors are also used to measure media temperature to control bottom heat systems.
Thermal couples are inserted in the propagation medium (arrow).
These send temperature readings to a control system that activates a solenoid to activate hot water bottom heat systems.