Certified GKH Gardening Expert
It really depends on many factors, such as the temperature while watering and the size of the tree. I would say that you need at least 2 inches (5cm) per week covering the entire area under the canopy. In hot weather (over 30 C), I would increase that to 4 inches (10 cm) per week. That is for a plant in the ground. If it is in a container, water daily in weather under 30 C and twice daily in weather over 30 C.