I have had a lot of questions lately about how to properly water trees. Even established trees need a good soak of 12-18 inches deep within their dripline when we experience hot and dry weather. I found a little bit of information that explains a few ways to help make sure your tree is getting the water it needs during the dry times of the year. As always, if you need any help, you can get hold of me by calling 620-793-1910, emailing me at aboor@ksu.edu, or coming into the office at 1800 12th Street in Great Bend.
Newly planted trees have not established the extensive root system needed to absorb enough water during hot, dry, windy summers. Even trees 2 or 3 years old should receive special care.
Deep, infrequent watering and mulching can help trees become established. Newly transplanted trees need at least 10 gallons of water per week, and on sandy soils they will need that much applied twice a week. The secret is getting that water to soak deeply into the soil, so it evaporates more slowly and is available to the tree’s roots longer. One way to do this is to punch a small hole in the side of a 5-gallon bucket and fill it with water. Let the water dribble out slowly next to the tree. Refill the bucket once, and you have applied 10 gallons. Very large transplanted trees and trees that were transplanted two to three years ago will require more water.
A perforated soaker hose is a great way to water a newly established bed or foundation planting. In sunbaked soil, you may need to rough up the surface with a hoe or tiller to get water to infiltrate easily. It may be helpful to set the kitchen oven timer, so you remember to move the hose or shut off the faucet. If you are seeing surface runoff, reduce the flow, or build a berm with at least a 4-foot diameter around the base of the tree to allow the water to percolate down through the soil, instead of spreading out.
Regardless of method used, soil should be wet at least 12 inches deep. Use a metal rod, wooden dowel, electric fence post or something similar to check depth. Dry soil is much harder to push through than wet.
Inexpensive Method of Watering Trees
We mentioned in an accompanying article about using a soaker hose to water trees. We thought it might be helpful to provide more details.
Soaker hoses are notorious for non-uniform watering. In other words, you often receive too much water from one part of the hose and not enough from another. On small trees, circling the tree several time with the soaker hoses will even out the amount of water applied but this isn’t practical for larger trees. Hooking both the beginning and the end of the soaker hose to a Y-adapter helps equalize the pressure and therefore provide a more uniform watering. The specific parts you need are shown in the photo above and include the soaker hose, Y-adapter and female to female connector.
It is also helpful if the Y-adapter has shut off valves so the volume of flow can be controlled. Too high a flow rate can allow water to run off rather than soak in.
On larger trees, the soaker hose can circle the trunk at a distance within the dripline of the tree but at least half the distance to the dripline. The dripline of the tree is outermost reach of the branches. On smaller trees, you may circle the tree several times so that only soil which has tree roots will be watered.

Alicia Boor is the agriculture and natural resources agent for Barton County K-State Research and Extension. Contact her by email at aboor@ksu.edu or call 620-793-1910.