I have a thermometer encased in black plastic hanging at the top of my canopy. Since it is black the temperature it gives me is about 5-10 degrees (F) hotter when it is directly exposed to the light. I currently have a white piece of paper shading it so that it gives me a more accurate reading of the air temperature. That made me realize that the air temperature and the temperature of dark colored objects under the light (e.g. 
) are two different things. My air temperature is usually good when the light is on, but how do I know if the plants themselves are at optimal temperatures?
) are two different things. My air temperature is usually good when the light is on, but how do I know if the plants themselves are at optimal temperatures?
