Everyone knows that correctly watering a tree is one of the most essential practices for making sure that your trees flourish and stay healthy.
Of course, many trees can survive with little to no additional water, but if you are concerned with giving your tree the longest and healthiest life, you will want to take some responsibility for watering it.
Certainly, if you plan on planting or growing a tree from seed or sapling, knowing the steps for correctly watering a tree is paramount.
This complete guide explains exactly why watering a tree properly is crucial for the success of your planting, and explains the process to avoid both overwatering (Which can be detrimental) and underwatering.
It also outlines why it is best to water along the tree “drip line” and how to properly water your seedlings so that they can grow strong and develop healthy root systems.
Watering a Tree: How To Water a Tree
There are many ways to provide the trees water needs, this article will explore how to water a tree. Perhaps the most basic tried and true method is simply to take a soaker hose, and deeply soak the ground under the tree along the line directly under the edge of the canopy.
This is how the majority of water would fall onto the soil in natural conditions – i.e., during rain, and encourages deep and wide root growth for a healthy tree.
How Much Water Does a Tree Need?
How much water does a tree need is highly dependent on a number of factors including the tree type, planting area, growing zone, soil type, etc. One of the most important factors that translate across virtually all tree types is simply the tree’s age.
Although most plants can absorb water through their foliage,6 the biggest way for trees to capture water through the surrounding environment is through their roots.
Most tree root systems are very impressive, they can often extend to a greater diameter than the tree’s total height and can grow extremely deep, depending on the species of tree and environment.
Connection Between Trees, Water and World Health
Trees and water are something we often take for granted. Everyone knows it is essential for life on Earth, but because an enormous proportion of Earth’s surface is covered by water, we often don’t have to think about how to apply it to grow plants.
The fact is that only around 3% of the Earth’s water is usable for agriculture, including to water trees in your garden. Some have estimated that water availability is the greatest limiting factor in worldwide tree growth.
Tree roots are covered by tiny hairs and beneficial fungi which help them draw water in with osmosis. This just means that it creates conditions on the inside so that water wants to move in from the outside.
Once the water enters the root system, it operates according to a natural phenomenon, or a set of phenomena known as transpiration. This basically just refers to the movement of water within the tree and its release into the air.
Trees can absorb between 15 and 150 gallons of water a day but in fact, a very very small proportion of this water is actually applied to tree growth and metabolism. Around 97% to 99% is lost by expiration or guttation.14
The first term just refers to moisture lost as water vapor, and the second refers to water lost in a liquid form, for example as tree sap. As for the first, most leaves are covered in tiny pores called stomata.
These can often be felt as a texture on the underside of a leaf. These same stomata which release the water vapor absorb carbon dioxide for photosynthesis.1
Young trees need to deal with proportionally high stress, grow quickly, and expand their root systems into the soil. This means most of them require deep and consistent watering to thrive.
Watering a New Tree
There are many factors that contribute to the survival probability of a new tree. Besides species choice and placement, maybe the most important is watering.
Usually, if a tree can survive the first two years in the ground, its chances of a long life are high. So watering a tree is essential, especially in the first two years.
The most important quality for watering a new tree is that you water slowly and deeply. This may sound simple, but usually, a simple sprinkler or drip lawn system won’t accomplish this adequately or without enormous waste.
Such systems allow water waste through evaporation simply due to imprecise application.
For you to adequately water your new tree with this method you would have enormous water waste, driving up cost and unnecessary environmental impact.
In fact, you would risk damaging the trees within the vicinity of the watered area, which would likely be over-watered with the amount necessary for your new tree.
Using Perforated (Drip Hoses) and Soaker Systems
The recommended method is to place a hose, either a garden hose or soaker, pointed at the base of the tree.These are special hoses that have holes at increments, allowing the water to soak the ground along the drip line of the tree.
If you use a regular hose, don’t point it at the trunk, point it around the outside portion of the root ball to avoid having an over-watered tree.
Sometimes a simple hose stand can help with this. Then turn the hose on low and provide a light stream for around two hours, changing the position to hit the roots from several angles to ensure even growth and development.
(Image: StephanieAlbert18)
The first time it might even be worth it to actually dig or place a tester down in the soil to verify how far the water reaches. During the summer months, this is recommended every week from May to October.
Obviously, if experiencing sufficient rainfall, you should skip the process and wait for the soil to dry first.
It should go without saying that these processes are dependent on the tree species and climate. Some species, such as Palo Verdes, will require less, especially if planted in a relatively wet area of their growing zone, while the reverse applies to water-loving trees planted in dry areas of their growing zone.
The type of soil and the lie of the land are also important factors. When watering a newly planted tree there is always a question of whether can you overwater a newly planted tree or when to stop watering new trees.
In most cases, you should make sure the soil has the opportunity to dry before your next deep watering.2
Tree Watering: How Often To Water Trees (Water Tree)
Correctly watering a tree or tree watering depends on a number of factors including the tree’s species, age, size, and environmental conditions such as soil type. Young fast-growing trees will require the most amount of water and the most frequent watering.
So, how often to water trees? A good estimate for the average tree in North America is that it wants a thorough soaking around the edge of its canopy around once per week. In any case, make sure that the soil has a chance to dry completely between watering.
Overwatering is just as possible as under-watering.11
How Often To Water Seedlings
Watering seedlings is a delicate procedure and many people wonder how often to water seedlings?
Usually, the best way to water is once a day with a simple spray bottle, depending on the size of the seedling.
You can also put a glass bottle over the top to maintain a warm and moist environment. Water enough with the spray bottle to keep things moist, but you do not want your seedlings sitting in water, so make sure there is a way for the soil to drain.
As the seedlings grow and mature, you can take them outside to harden off and acclimate to natural conditions.
Watering Trees During Drought
Correctly watering trees during drought can be a difficult task. Unless you have a drought-tolerant species like the Palo Verde Tree which at its peak maturity can withstand even severe drought conditions, you will probably want to water your tree more often during this period.7
The ideal way to do this is with overhead sprinklers, although obviously, not everyone has these available. In any case, the most important thing is to apply deep and even watering over the entire root zone of the tree.
Root zone sizes can vary, but young trees can have a root diameter as wide as their height. It’s necessary to water so wide to encourage deep and wide root growth.
If you simply water the top you will promote shallow root growth which can cause all types of health issues for the tree.
So water deep and wide. The soil should be moist down to about nine inches.
Another tip is to water either early in the morning or late at night. This will minimize water loss due to evaporation and help save the amount of water necessary.
Another way to conserve water is to apply mulch in a ring around the base of your tree. Make sure to leave space between the mulch ring and the stem.
You don’t want to cover the trunk of the tree at all when mulching around trees. This mulch will help your soil retain moisture during drought and could reduce the amount of water necessary to keep your tree healthy.
Watering Trees in Winter
Correctly watering trees in winter is not usually a challenge, because most trees are dormant in this season.
This means they are not performing most of their energy-consuming functions such as blossoming or rapidly growing. However, they are still alive and as such need water.
We may not think of this as a big concern in the winter because we associate drought with heat, but winter can be just as dry, especially under the soil.
You may not notice the winter drought damage to your tree until spring. This is why winter watering is so important.8
Keep a regular watering schedule through the fall, once the ground freezes, it’s important to keep an eye on the weather. It is recommended to water the tree relatively thoroughly, as during the summer, however only when the temperature is above 40 degrees Fahrenheit and there is no frozen water on the wall surface.
At lower temperatures, the water may actually cause frost damage to the roots of your tree. A good practice is to water midday, when the soil is warmest, so the water can be absorbed by the tree and dispersed through the soil before the cold returns at night.
As always, new trees will want more water. A good cursory way to check the moisture of your soil is simply by digging in two to three inches and gauging with a touch.
The desired moistness will be dictated by your tree type and the location of planting. In any case, when watering make sure to water the entire surface above the root ball.
It is usually not recommended to water the foliage of any types of evergreen trees during winter.3
Tree Drip Line
Drip lines usually can refer to two different types of systems: one for trees and one for general irrigation. In the context of trees, it basically refers to the ring around which rain falls.
Because most trees have thick canopies shaped like umbrellas like the Maple Tree, Poplar Tree, Sycamore Tree and Hornbeam Tree, the water doesn’t fall evenly around the tree trunk. It falls mostly along and then outside the canopy line.
This is what’s known as the drip line, also sometimes known as the Critical Root or Root Protection Zone.
Although it is not always very circular, it is sometimes most convenient to estimate it in the shape of a circle.
This means that the majority of the water available to the tree actually comes through the soil at or outside of this zone, which explains the need for extremely wide and developed root systems.
This is also why it is so important to water a tree out wide and thoroughly, watering along the trunk means that your tree is liable to develop malformed and shallow roots.
Watering too much on the trunk also exposes your tree to various infections and diseases, the most common of which is probably root rot.
How To Do Deep Root Watering: Deep Watering Trees
In reality, almost all trees should be watered according to deep-root watering. Most trees want deep and wide root systems to be healthy.
The roots will grow where there’s water, so when watering a tree the best practice is deep watering trees.
A great way to do deep root watering is with a simple soaker hose.
The first step is to this method is to identify the width of the tree’s canopy.
Then water the ground perimeter that is directly under the canopy edge. This may take up a significant distance, but the great part is, it is the most efficient place to water.
Water thoroughly, so that the water soaks deeply into the ground. This needs to be done only around once a week for most mature tree species.
And of course, if you live in an area with significant rainfall around once a week, you likely will not have to give your trees any supplemental water at all.
How Important Is Watering Trees? Do All Trees Need Watering?
All trees need water but not all trees require human (supplemental) watering to survive. Usually, human-grown trees are not grown in similar conditions as it is in the wild which means they will likely not be as healthy.
In addition, in the wild, it’s not necessary for one seed or sapling to succeed, however in human-controlled environments, when a young tree is planted, it’s expected to reach maturity.
To increase the likelihood of growing a tree and the health of a specific specimen, watering should be a top consideration.
Watering a Tree: Watering Different Tree Types
A lot of the guidelines for appropriate watering change with different types of trees. It’s important to consider your species to avoid tree over water or under water.
It’s not just a question of whether or not the tree likes more or less water, but also factors like age and how long does it take for a tree to grow. Here are just a few examples:
Palm Tree
A newly planted Palm Tree can be watered every day for around the first two weeks. Then the interval can be gradually increased.
Unlike most other tree species, Palm Trees should rarely ever be in completely dry soil,13 although mature Palms are very hardy against relatively extreme moisture conditions.
The best time for watering a palm tree, as with most other trees is either early in the morning, or later in the evening.
(Image: sarangib16)
Lemon Tree
Mature Lemon Trees in the ground usually do well with watering about once a week. New trees could use around two to three times that frequency.
Lemon Trees are native to relatively arid environments so watering a Lemon Tree should take place when the top two inches of soil is dry.
Make sure the water penetrates deep around the edge of the canopy. If your Lemon Tree is potted it will likely require more.
Bonsai Tree
Watering a Bonsai Tree is probably the most difficult to generalize, as the trees are notoriously finicky. It really depends on your tree and soil.
However, as a general rule, you don’t want the soil to completely dry out and, when watering, the entire root system should be soaked.
(Image: robbrownaustralia17)
Also, watering should be done gently to prevent erosion of the soil. Usually, rainwater is recommended for such a sensitive tree.
What Is Root Rot?
Root rot is a generic term for various rotting conditions created by low-oxygen conditions in the soil around roots.9 This may occur as the result of standing water around the roots of the tree or the plants under the tree.
Obviously, different plants have different tolerances for soil moisture. If you water only towards the trunk, in order to give your tree enough water, you are concentrating more water in less space, creating the conditions for rot.
The rot itself is usually caused by various kinds of water mold, the most common species is from the Phytophthora.12 Once a plant is infected, the mold can migrate, either through spores or as carried by insects.
It can be lethal, although survival time varies widely. Unfortunately, there is no known cure.
Long story short, water widely around your tree’s drip line, not on the trunk. Money Trees for example are notoriously susceptible to root rot, when considering Money Tree care or watering a Money Tree make sure it drains between waterings.4
How Do I Avoid Root Rot When Watering a Tree?
Root rot is a generic denomination for a host of diseases that afflict a tree and can cause rotting of the roots or stem.
Usually, these are caused when the ground around a tree’s stem is habitually waterlogged.
The best way to avoid this is to make sure that the trunk does not have mulch or soil piled up in a volcano shape around the base, and also that the tree is properly watered and drained. It should be watered deeply along the ground under the edge of its canopy to imitate where and how rainwater would collect on the soil.
Tree Watering Systems
Watering a tree with a soaker hose is likely the best option for the average homeowner. However, some professional landscapers prefer to install tree watering systems.
There are many different types of such systems. For example, there are drip irrigation systems, which gradually dispense water out of a tubing line.
You can even set up a system for watering trees with 5-gallon bucket. There is also automation for hoses and above-ground sprinklers.
And there are various types of rotor attachments or volume limiters that can control the target area and volume of water desired. The next section will explain the drip line system as an example.
Drip Line in Irrigation
Drip irrigation is a type of watering system that, as the name suggests, drips water onto the soil above the root zone of the target plants.
As opposed to other watering systems, it does not require a high degree of water pressure, and dispenses water extremely slowly, making it low-volume, because it is dripping directly from a line, the method is considered to be precise.
One downside is that because of the low volume, it is not recommended for extremely hot environments with aggressive soil evaporation. The method mostly is intended to keep the soil around roots moist.
It is considered to be more sustainable than most types of surface irrigation, which is where water is poured over an uneven field and distributed by gravity. One of the main concerns with drip irrigation is that, when the drip is not sufficient, only the upper area of the soil will become moist, encouraging shallow root growth.
(Image: Agne2715)
This is why it is commonly used for shallow growing crops, rather than trees. The basic components are tubes with a diameter of around a quarter to a half inch with tiny plastic parts attached, called emitters, which basically allow a regulated drip.
Drip Irrigation for Trees
If you think that your tree and environment would be suitable for a drip irrigation system, you can buy a kit online. These kits come in many different forms to suit different needs.
However, they will almost always be much more expensive than a simple system you can put together yourself. The benefits of doing a DIY drip irrigation for trees are that it will likely be significantly cheaper and it will be perfectly suited for your needs.
Kits attempt a one-type fits all approach, and you will likely get better results from a system tailored to your exact needs.
Making a DIY Drip Irrigation
Here is a basic procedure for creating your own drip irrigation system.10 First thing you will want to have is a Y-ball valve. This kind of valve has two independent water outlets.
This just means that the drip system can be supplied from the same hose bib as your regular garden hose.
The next thing is that you will want to install a backflow preventer or breaker into one side of the valve (the side that will be for the drip irrigation system) just to prevent any water in the system from flowing back into the home’s water supply.
The next step is somewhat optional, it is to screw a digital time with a hose attachment into the breaker. This will allow you to regulate the amount of water that flows through your system to your plants for a given amount of time.
Otherwise, you will have to manage it manually.
Next, screw a mesh inline filter onto the timer to simply prevent particulates from running into the irrigation system and potentially clogging emitters. Usually, 120 mesh is recommended for this.
Next is a pressure regulator which would drop the regular hose bib pressure down to around 25 to 30 psi. This is important because, at regular pressure, the water could be distributed too fast and cause erosion or other problems.
Next, you will likely want to attach a hose adapter that will allow the rest of the system to fit into a half-inch drip line.
Next is the material for the actual drip irrigation tube. The most common choice here is a half-inch polyethylene tubing.
The length required obviously depends on the area and the distance from the hose system.
It’s important that you don’t use a material like PVC because it has been found to leach toxic plastics and stabilizers into water and other contact materials. It’s not the sort of irrigation pipe you want to water your garden.
(Image: fotoblend19)
Again, the best material is probably HDPE (High-Density Polyethylene). It should be easy to find.
It is important that the irrigation tube spans the circumference of the tree drip line, that is, the edge of the tree’s canopy. This is where, in natural conditions, the majority of rainwater would land.
It is important to water your trees so that they can develop a proper and healthy root system. Watering your tree too close to the trunk makes it susceptible to potentially lethal conditions like root rot.5
Installing DIY Drip Irrigation
First, unroll your polyethylene tubing to the circumference of your tree drip line. Again, this simply denotes the line which follows underneath the outer edges of your tree’s canopy.
Then simply insert one end of the drip line into the end of the hose adaptor. Any excess tubing can be simply cut.
The other end of the tubing should have a compression cap on it so water does not run out of the end.
Emitters usually want quarter-inch holes which should be drilled into the top of the tubing at regular intervals. If you have purchased a premade kit, it will likely include a hole punch mechanism specifically for this task.
Otherwise, simply use a drill bit or other serviceable method. For the holes, twelve-inch intervals tend to work well for sandy soil which drains relatively easily, eighteen inches is preferred for loam, and twenty-four inches is common for clay.
Drip emitters usually come with a barb on one end. This is the end that should go into the quarter-inch holes.
Then the tubing should be arranged with the emitters standing up so that the water can flow freely from them.
You will probably also want to stake your line into the ground to prevent it from moving or rotating with natural disturbances or the weight of the emitters. To do this simply take some U-shaped stakes, they don’t have to be specially made for the purpose, even U-shaped metal pieces will do, and then push them over the line, pinning them to the ground until it is secure.
Next, you will want to test your system. Turn on the water supply and try all of the components like the digital timer according to the manufacturer’s instructions.
You may want to start with a flow volume of half a gallon up to four gallons for young trees, depending on your specific tree and its conditions. As your system continues working throughout the days and weeks, be sure to monitor both the soil and the health of the tree to determine that it is achieving the desired result.
The most important thing to remember is that a drip line irrigation system should water deeply around the edge of the roots of a tree, not shallowly, and not close to the stem (the trunk).
The best alternative to a drip irrigation system is once-a-week dowsing with a soaker hose, again around the canopy perimeter. This may actually be more efficient, more sustainable in terms of water, more affordable, and more convenient depending on your specific situation.
Thus correctly watering a tree might mean simple deep water soaking using a hose around the width of the canopy once a week.
Learn More About Watering a Tree
Self-Watering Planters That Use 1 Secret Irrigation Method Rarely Understood
Is the Vitamin Water Good for You? You Might Be Surprised To See This
Money Tree Plant Care: Avoid This Common Mistake (How To Water Indoors)
Can We Live Without Trees? How Our Worst Fears Are Becoming Reality
Water Conservation for Kids: Quiz Your Knowledge!
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