How often should I water my fruit tree?
Too much and too little water are the two main causes of fruit tree failure. Fruit trees should be watered only when the soil is on the verge of becoming dry. Irrigation frequency during the growing season depends on temperatures, soil type and mulch - as well as how fast the trees are growing: vigorously growing trees use up available water more quickly.
Fruit tree roots, for stone fruits especially, do not tolerate wet soil (saturated, oxygen-deprived soil) for long. With slow-draining, heavy clay soils especially, it is important not to water too often, then water deeply to reach the entire root zone.
Bareroot trees newly planted in sandy soil may benefit from frequent light watering to maintain moisture near the emerging feeder roots. Form a basin in the soil around the tree to direct water to the roots and away from the trunk. Overwatering in sandy soil can leach nutrients away from the root zone.
In most situations, irrigation during the dormant season is required only during an extended dry spell.
Get to know your soil by digging down 12-18 inches periodically between irrigations to see how wet or dry it is, keeping in mind what the temperatures have been and how the trees have been growing - and/or learn to use a soil moisture meter.
For more, see Water and Mulch. For information about planting fruit trees in slow-draining soils, see Planting Your Backyard Orchard.