"Measured EMG potentials range between less than 50 μV and up to 30 mV,"
so if you are trying that you will need a much higher gain.
I've never looked at signals from plants, it will be fun to try but you may see electrode potentials.
Again you may need a lot more gain.
From what? How?
A graph without X and Y labelled is no use. Are they volts? microvolts? Amps? Is the Y axis Height? Humidity? Tiime (microseconds or days?)
The Y axis is the Analog readings in Volts after the plant signals have been passed through the amplifier. X axis is the time (each reading is taken in 100 milliseconds).
Hi, @enligio
What are you using as a calibrated signal source for your tests?
Can you please post your circuit?
Can you please post your code?
Tom... 
To know what voltage your analog reading corresponds to you will need to calibrate the system.
