How to Water a Tree

Is it silly to have a page on How to Water a Tree?
Many people I talk with do not know how to water correctly. They've never questioned the methods they were using. They just poured water on until they felt it was good enough.

Essential Tree Roots

Tree roots will spread out at least as far as the drip line of a tree and sometimes farther.
So whats a drip line?
If you took a string and dropped it towards the ground from the tip of the widest branch, that would be one point on the drip line. You would then do this all the way around the circumference of the tree creating a huge circle on the ground. This is your drip line area.
Essential "feeder" roots are growing all around the drip line area.
On new trees the drip line area is small. On mature oak trees the drip line is huge.

Water the Essential Roots

If you aren't watering the whole dripline area, you aren't watering all the essential feeder roots.
Feeder roots lay in the top 12" of the soil. You need to make sure when you water a tree that the water gets down to a depth of 12 inches.

Newly Planted Trees

When you planted your tree, you put it into a hole that was on average 2 foot deep. Some holes might have been deeper. When you had your new tree out of the container, you most likely saw that it had roots all the way to the bottom of that mass of soil. Those roots need some water too. Getting water to them can only be done through soaking the ground.

How to Water A Tree

The best way to water a tree is by laying the hose of the ground and letting the water soak in.

You want the stream of water coming out of the end of the hose to be about pencil thick.

If the water is running off faster than it is soaking in, decrease the flow.

This method takes time, but deep thorough watering is best.

For established trees (planted one year or longer) you can set up a sprinkler system and let it shower the area. The length of time you let the sprinkler run will depend on how well your soil soaks up the water. If you have mulch on the ground it will take longer as the water has to get through the mulch to reach the soil. I set my sprinkler and leave it run for a couple of hours. (there have been a few times when I've forgotten it and ran the sprinkler over night!)

How Often to Water

For newly planted trees, you can typically get by with a thorough watering once a week. If you have a good rain during the week, you can usually skip the water for that week.
Don't use the calendar to set a schedule. Don't water just because it's Monday and you watered last Monday.
Test the ground to see if its moist or dry. If it's moist wait a day to check it again. If it is dry, you should water it.

Established trees can usually get their water supply from nature. Trees under four years old you should keep an eye on and water if they look distressed. Trees five years and older can be left alone except during extreme hot and dry spells. Giving them a drink of fresh water can help keep them from getting stressed.

Drowing and Thirst Look the Same

When observing your tree you would think it is easy to tell if you are giving it too much or too little water. The leaves start turning yellow and/or wilt. Sorry, Mother Nature strikes again. She made the physical symptoms on drowning plants look exacly the same as on thristy plants.

Wilting leaves can happen from too much water, just as easily as from too little water.
Yellowing of leaves can be cause by too much water just the same as from too little water.

A thirsty plant can be resurrected if it's caught in time. Just add water and in an hour or two it perks back up.
A drowing plant might not survive, it is too hard to soak up the excess water from the soil. (I've tried, the sponges just end up all muddy!)