The heat pulse method is used for determining transpiration based on the amount of water flowing within the stem of perennial crops such as cacao. The objectives of this study were to determine hourly transpiration from a sap flow meter and estimate crop coefficients (Kc) at different stages of development in order to determine crop water requirements. It is concluded that the heat pulse method and sap flow reasonably estimate the transpiration of cacao trees and properly detect flow direction. Transpiration in cacao varies from 10 to 40 liters per day, in a 10-year-old tree during the irrigation requirement period. The Kc values estimated with shade trees during their growth and development vary from 0.6 to 0.7 in the months of February to May, when irrigation is required due to the water deficit that occurs according to the crop water balance.

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