What sensors to measure grass growth? I would like to make a small project, which would allow me to recognize if the grass has grow enough to lawn. I don't know too much the ecosystem of available sensors for such problem. And I have a lot of grass and some irregular areas to clean once in a while.

Is that something I can do with an arduino and some sensors, or should I need to use more processing power and cameras/AI?

TIA!
My idea: Two light sensors on a short stick embedded in the ground. If the top sensor detects light, but the bottom one does not it means that it's daytime, and grass is long enough that it covered the bottom sensor. You will probably need several of those, because there is no guarantee that grass will actually cover the bottom sensor, and you will need to filter out random elements by testing if values don't change to much.