ESP32 maximum capacitive Soil sensors

Hi all,
Im wondering a bit if there is a maximum amount of capacitive soil sensors I can drive of a single ESP32, with the ESP also being the power source for the sensors. I have a working setup with 3 sensors currently, but want to expand over using only 3.

Anyone with experience how much are the theoretical maximum I can get running? Or is the power supplied from the ESP well enough and only limited by usable ADC pins?

While I’m sure there are improvements to be made by juicing things up, all I can say is that I have several ESP’s in my grow tent right now with 4 capacitive moisture sensors hanging off of each of them without any additional power input. Other than the fact that those sensors don’t last long due to delimitation (but they are cheap so whatever), it works fine.