I learned on another forum that you should water succulents in the evening on hot days. Because succulents use a form of photosynthesis call CAM (Crassulacean Acid Metabolism) and halt their uptake of water during periods of intense sunlight and heat.
With CAM photosynthesis the stomata on leaves stay closed during the day and open at night which allows transpiration which allows the uptake of water. During the night the plants take in CO2 and store it as starches for use in photosynthesis during the day. Oxygen is released during the night also.
So the main point is with CAM plants on hot days the stomata are closed which means no
transpiration which means no uptake of water during the day.
