Well…as it seems you know, an exposed sensor probe is going to give you probe surface temps, not ground surface temps. Sure, the readings will behave in much of the same way, but I’m not sure how representative the probe is to actual ground/grass. If you can find something with the same albedo as your particular surface type then I would think that would work. The albedo of specific materials is not my thing so I’m not much help. How would you describe your ground surface and soil type?