How to water fruit trees varies from tree to tree. There are many kinds of fruit trees and while there are some general rules you can apply to all, it is best to follow guidelines for your specific tree. However, no matter what kind of fruit tree you have, to make watering more efficient, add a couple inches of mulch around the base of your tree to help maintain moisture. In addition, adjust watering schedules when it rains. A good rain can count as a watering.
Water young fruit trees every day for the first one or two years after planting, if possible. This is especially true on hot, dry days and for subtropical fruit trees like mango trees.
Water mature subtropical fruit trees, such as citrus and avocados, more frequently than other types of trees, like apple or olive trees. Generally, watering subtropical trees a couple times a week will suffice. However, some trees like papaya trees need water every day. Other trees like apple and olive trees need to be watered about once a week during their growing seasons.
Water using drip irrigation if possible. This is a method where you water the roots under the ground rather than watering the top of the soil. There are drip irrigation kits available for purchase at local and online nurseries. If this is not an option for your, use a sprinkler, or the rain setting of your hose and evenly water under the entire canopy of your tree, with more water toward the center and less as you go outward where roots are smaller. Water a couple inches, slowly.
Avoid over-watering. Be sure you know your specific fruit trees watering needs. If you over water, your tree might develop root rot and die.