Oak trees can withstand most soil and weather conditions. However, newly-planted oaks need a bit more water than established trees. In addition, during dry spells and before the winter, oak trees will benefit from a good watering. Place a 2-to-3 inch layer of organic mulch, such as bark or wood chips, under the canopy of your tree to help retain water. Replace the mulch as it decomposes.
Water oak trees that were planted within the last three years once a week during the growing season, usually from early spring until early fall.
Water established oak trees only during long dry spells. Test the soil with your finger about 4 to 8 inches deep. If it is dry or just slightly moist, water the tree.
Water oak trees in the fall or early winter before the ground freezes. This will give the tree the water it needs for the winter months.
Place the hose near the base of the tree to water it. Turn it on for a slow trickle and leave it there for about three to five hours. This will slowly saturate the soil around your tree without getting the trunk wet.