Pecan trees, the state tree of Texas, grow wild along the banks of rivers and streams throughout the southwest. They thrive in moist, well-drained soil and need irrigation throughout the growing season from mid-March to September. Without adequate moisture, their growth dwindles, the edges of the tree's leaves look burnt and fruit production is of scant, poor quality. Trees planted in fast-draining, sandy soil need more water, while trees planted in clay soil quickly become waterlogged and require less water, applied slowly.
Build a water ring 4 to 5 feet in diameter around the base of the pecan tree by mounding soil up 3 to 4 inches high in a circle with your hands. Water a newly-planted pecan tree with at least 5 gallons of water.
Water pecan trees weekly during the growing season with at least 1 inch of water. Lay a hose on the ground or run a sprinkler for at least 45 minutes during each watering session. If the pecan tree sits in a lawn where it will compete with the grass for moisture, provide extra water. The root system of a pecan tree is at least twice as wide as the canopy of the tree, so water the area around the pecan tree to reach the roots.
Cut back watering of young trees to every two weeks in late August to September. This watering schedule allows the young trees to slow their growth and harden off before cold weather comes. Continue watering mature, nut-producing trees weekly until harvest is over.
Water pecan trees every six to seven weeks during the winter, especially if no rain has fallen.