I am not entirely sure if this is the correct forum to ask this question so please refer me on if there is a better arena.
I am creating a small weather station and I wish to measure soil temperature. I am aware that digging a hole and then burying the sensor will alter the aeration of the soil and therefore give imprecise readings. I have therefore decided to integrate the sensor into a notch in a steel tube and then drive this tube into the ground. This means that there will be minimal disruption of the soil composition and the sensor will touch the soil both inside the tube and outside.
My concern is that the steel pole will retain heat differently to the soil (both from any showing to the sun above ground and more generally below the ground) and in doing so skew the temperature readings. Can you recommend a coating that I could put on the metal to reduce its conductivity/radiative properties and therefore minimise its impacts on the sensor?