Article Highlights
New trees require weekly watering for at least two years
Find a method that's FAST, so you'll stick to it
Find a method that's EFFICIENT, to conserve water
Compare commercial products below or at www.sayegrow.com/wateringmethods
Use These General Guidelines
Tree Watering Frequency
Daily temperatures, rainfall, time of year, and soil type all have an effect on watering frequency. But the best approach is to periodically check the soil and gain a feel for when to water. Once per week is usually adequate, but if the soil ever becomes drier than a damp sponge, increase the frequency. Never water if the soil is already wet.
Establishment Time
It will take some judgment on your part, but tree growth is a good indicator. Once your new tree has doubled in size, you can be sure that the root system has taken a good foothold. This may take 3 to 5 years.
Quantity per Application
Newly planted trees with less than a 2” trunk diameter will have a root well of about 5 cubic ft (24" dia. x 20” deep). Since typical topsoil will saturate at about one gallon of water per cubic foot, it should only take 5 or 6 gallons to soak the root well. It could be wasteful to exceed 10 gallons on trees of this size, but be sure that you are efficiently applying at least 5 gallons.
Problems to Watch For
Inadequate Watering
Roots develop where moisture is available. This is why light surface watering can be harmful, promoting shallow root systems while starving the deeper roots. This type of development leaves the tree at risk of winter injury, summer heat stress, and wind damage.
Over-Watering
Too much water can be just as bad as too little water. It may not seem intuitive, but tree roots actually need to breathe. Excess moisture pushes oxygen from the soil, and without a drying period, roots will slowly begin to die. One symptom of too much water is the unexpected lightening or yellowing of leaves starting on the lower part of the tree and slowly move outward. Other symptoms may include wilting of young shoots or brittle green leaves. Watering once per week is usually adequate, but never water if the ground is already wet.
Excess Mulch
Most experts agree that proper mulch depth is 3-4 inches, enough to shield the soil from sunlight and control competing grasses. Deeply piled mulch is commonly used to hold water to speed up the process, but there are three flaws with this technique. 1) Mulch does not stop water-runoff, 2) roots will develop above the soil, and 3) mulch around the trunk flare can cause trunk rot and eventual death.
Choose a Tree Watering Method
Watering methods include open hose, soaker hoses, drip-irrigation rings and bags, hose-fed root feeders, and self-contained root feeders. You should become familiar with each of these methods. Choose one that does the job using minimal time so you can stick to a weekly watering program. WARNING: If it takes too long you won't do it and your trees will suffer!
Traditional "Open Hose" Methods
This is the default method of watering trees. Unless you construct a sizable soil dam around each tree, it will require a minimum of 10 minutes per tree. Soil dams require periodic maintenance due to erosion and mower damage. Automatic shut-off timers are also available for hose-watering, but is still long-term babysitting job for multiple trees. Disadvantage: Time and water waste.
Soaker Hose Methods
Soaker hoses are a commercially available and relatively inexpensive way to water. They can be used on trees, but they are much better suited for flower beds and shrubs. Soaker hoses don’t provide any peace-of-mind for volume or depth, and they are simply impractical for multi-tree applications randomly located in a yard area.
Drip Irrigation Methods
Drip irrigation is a very common method of watering trees. There are several types of drip irrigation, including self-contained bags, self-contained rings, and semi-permanent emitter systems. This category has a higher cost associated with it, but the time savings over the hose methods may be worth it.
Self-contained means the method has its own reservoir. You must use a hose to fill it, but it will fill fast and then drain at a pre-determined rate. The bag unit sits on the surface and is portable, where the ring products are semi-buried and meant to be left at the tree. In order to finish your weekly watering quickly, you must acquire a complete unit for each tree. Both methods use small holes to regulate the flow from the reservoir to stop run-off.
Emitter systems are available in kits. They include hose that must be networked to an emitter unit located at each tree. Attachment to a water supply is usually permanent and a timer can be used for automatic watering. Once the set-up is engineered and properly assembled it is the ultimate in time savings, but the installation may be more than the average homeowner is ready to take on. Water pressure and emitter orifice sizing must be taken into account if you want to estimate quantity per application. It may also be impractical to use this method for trees that are remotely located.
All drip irrigation techniques are surface watering. Since you are soaking the surface, including mulch, more water is required to reach the deep roots. Unlike a root feeder, you can never be certain of the depth. Drip irrigation is a better alternative than hose methods but still may not match the efficiency and time-savings of a self-contained root feeder.
Hose-Fed Root Feeders
The most effective method of tree watering is the deep root feeder. This technique involves some type of injector that actually forces the water to by-pass the surface and go directly to the root well of the tree. Run-off is no longer a concern and unwanted surface root development is minimized. There are two types of root feeders, hose-fed and self-contained.
A hose-fed root feeder attaches to a garden hose and requires 10 to 15 minutes per tree. The device looks really cool and each tree gets a good deep soaking, but this is still a one-at-a-time method. If you have more than 3 trees to water, the demand on time becomes too impractical for most people to bear. As with the other hose methods, quantity per application is also difficult to know. If you choose this method for newly planted trees note that if the water pressure is too high you can to boil air pockets around the roots of newly planted trees.
Self-Contained Root Feeders
The self-contained root feeder provides deep root watering along with the time saving advantages of attached reservoirs. They are self-regulating, meaning that they empty at the natural percolation rate of the soil. Tree I.V. from SayeGrow is a good example of this technique. A hollow plastic injector is permanently inserted near the base of each tree. Portable five-gallon buckets easily attach to the injectors and are filled in less than one minute. This means you can water 10 trees with only about 10 minutes of your time.
Root feeders also provide a good way to add nutrients. By applying them deep we can minimize the amount that gets stuck in the mulch or gets used by surrounding grasses. Although hose-fed root feeders sometimes have problems with clogging, a water soluble fertilizer must be used with the self-contained type.