## 3 Results and Discussions  
### Variability in Temperature and Humidity  
The indoor air temperature of a greenhouse can impact various factors such as water and carbon fluxes within the plant, fruit quality [41, 42], and energy consumption [43]. Air temperature also has an effect on the humidity condition. Therefore, the proper control and management of indoor air temperature is crucial to ensure optimal microclimate condi  
Figure 4: (**a**) Schematic diagram of the data receiving, processing, and transmission process, as well as the visualization and monitoring using the PLX-DAQ tool. (**b**) Data visualization using PLX-DAQ from the sensor nodes and gateway. Figure 3: Wireless sensor network (WSN) during the experiment: (**a**) positions of the sensors in both greenhouses, (**b**) sensor-to-sensor distance inside and outside of the greenhouse, (**c**) arrangement of the sensor nodes inside the greenhouse with plants, and (**d**) positions of the external sensors on top of the greenhouse. tions in the greenhouse. Figures 4 and 5 show the overall variability in the temperature and humidity inside and outside both greenhouses (with and without crops) during the experiments in the winter. The air temperature both inside and outside the greenhouse gradually increased to a peak value and then decreased over time. Significantly, the maximum indoor and outdoor temperatures occurred at different times, with a delay observed in the maximum indoor temperature. The hourly minimum and maximum temperatures outside the greenhouses were \(-9.2\)\({}^{\circ}\)C (8:00 h) and \(3.6\)\({}^{\circ}\)C (11:00 h), respectively; the hourly minimum and maximum humidity outside the greenhouses were 16.1% (13:00 h) and 94.2% (5:00 h and 6:00 h), respectively. The hourly average temperature showed an upward trend from 9:00 h to 12:00 h, followed by a gradual decrease thereafter. On the other hand, the humidity exhibited a rapid increase between 13:00 h and 15:00 h and continued to rise steadily until 7:00 h. The hourly minimum and maximum temperatures inside the CSG without crops were 8.84 \({}^{\circ}\)C (5:00 h) and 30.3 \({}^{\circ}\)C (12:00 h), respectively, and the humidity was 25.63% (12:00 h) and 94.26% (15:00 h), respectively. Similarly, the hourly minimum and maximum temperatures inside the CSG with crops were 9.96 \({}^{\circ}\)C (4:00 h) and 24.5 \({}^{\circ}\)C (12:00 h), respectively, and humidity was 32.6% (12:00 h) and 92.1% (5:00 h), respectively. The air temperatures within the two greenhouses followed a pattern that was quite similar. The inside temperature began to increase once the cotton blanket was removed at 8:00 h and reached its maximum temperature at around 12:00 h. Once the temperature started to drop, the rate at which the air temperature dropped slowed down when the blanket was placed over the south roof at 15:00 h. As shown in Figure 5, the air temperatures within the greenhouse were comparable whether crops were present or not, except for the lower layer, which was very warm (especially during the night). The temperature differences between the layers in both CSGs are also depicted in Figure 5, indicating a temperature difference of approximately 2.2 \({}^{\circ}\)C between layers in the CSG without crops and around 1.4 \({}^{\circ}\)C between layers in the CSG with crops. The daily average temperature inside both greenhouses was approximately 16.4 \({}^{\circ}\)C, which was higher than the average outside temperature. The humidity differences between the layers in both greenhouses are shown in Figure 6. In the CSG without crops, the humidity difference was lower throughout the daytime, and differences between layers were smaller compared with the CSG with crops. The differences during the night were more pronounced, and humidity was higher in the lower layer than in the top layer. During the day and night, the differences in the humidity between the layers of the CSG with crops were more pronounced.