The evapo-transpirations were measured by weighing lysimeter continually at every half hour for turfs of Cynodon dactylon x C. transvaalensis and turf of Sedum mexicanum which were important plant material for roof top gardens. Evaporation from bare soil was also measured. Air temperature, humidity, rainfall, wind and light intensity (PFFD) were measured consequently at every one hour. As results, among the environmental factors, light intensity and water vapor deficit were strongly correlated to the evapo-transpiration water amount. So, the averages were calculated at many combinations of the two factors. By the most cases except at the highest light intensity and the highest water vapor deficit, evapo-transpiration were increased according with the light intensity or increasing of water vapor deficit, and the evapo-transpiration were not so much different among Cynodon, Sedum and bare soil. The fact shows that there is no difference about the temperature effect among Cynodon, Sedum and even bare soil by water evaporation. At the highest light intensity and the highest water vapor deficit, Cynodon and bare soil accelerated the transpiration. It would lead to withering for Cynodon. But the Sedum turf decreased the evapo-transpiration and could be tolerant against dry up.