How make a polygraph plant sensor?

To create a polygraph plant sensor, you'll need a basic setup that includes a microcontroller (like an Arduino), soil moisture sensors, and possibly temperature and light sensors. Connect the sensors to the microcontroller and program it to read the data, which could be displayed on an LCD or sent to a smartphone via Bluetooth. Additionally, you can integrate a logging system to record data over time for analysis. Finally, ensure proper power supply and housing for the components to withstand environmental conditions.