Tree Irrigation: Doing it Right
Professional landscapers use different tree watering strategies for each stage of growth. The root system is intended to grow deep and wide to support the tree as it matures. Believing that tree roots naturally grow toward water is false if the soil surrounding them is dry. For proper growth, water should be sufficient to travel downward beneath the tree to a depth that encourages the roots to grow into a system substantial enough to support the developing tree.
Providing sufficient water during the early years increases the likelihood that the tree will thrive.
How Much Water?
While there are many variables in determining how much water to use, keeping the soil moist to a depth of 18 inches is a great starting point. The type of soil, temperatures, season, and the variety of tree are all factors to consider. Newly planted trees require more water to encourage root growth to help them become accustomed to their new surroundings. Soak the root ball and surrounding area thoroughly in the early weeks after planting.
Note that watering a young tree lightly, as with a typical lawn sprinkling system, does not allow for sufficient soaking to reach deeper roots. The water tends to run off or be absorbed before it reaches the thirsty roots.
Frequency and Proper Drainage
Trees, small plants, and grassy lawns have very different watering needs. Trees require a far greater quantity of water applied less frequently than with smaller plants. Deeper soaking can only be achieved with a slower yet longer application.
However, overwatering can be extremely harmful and “drown” the tree by preventing the roots from absorbing the oxygen they need to survive.
Also, if the water accumulating around the base of the tree does not appear to be flowing into the ground within seconds, clay soil could be the problem. Correct drainage is essential for the roots to receive the proper amount of moisture. Test the soil before planting. If the composition contains too much clay, mix with coarse compost to improve drainage.
Mature Trees
As a healthy tree develops and its root system spreads, direct watering at the trunk is no longer necessary. The better approach is to employ drip systems that encircle the tree, approximately at the drip line. The tree absorbs necessary water at the end of the roots and is encouraged to spread further as the tree grows.















