Water is key to the health and life of trees, but knowing  just how much, how often and when to water can get a little tricky. Some of the factors to consider are weather conditions, soil type and whether your trees are newly planted or well established.

The proper amount of water for trees is dependent on several variables, including the kind of tree, age, soil type, and local climate. Trees can suffer from both overwatering and underwatering.



Overwatering is the practice of giving plants or trees more water than they need, which leaves the soil and the area surrounding their roots too wet. Numerous causes, including inadequate drainage, over- or under-watering, and environmental conditions, can cause this.

Root Suffocation: An oxygen-starved root system results from persistently wet soil. This may result in root suffocation, which damages the tree’s capacity to absorb nutrients and water, causing general ill health and even death.

Root Rot: Overabundance of moisture fosters the growth of fungi that cause disorders like root rot. The stability and capacity of the tree to absorb water and nutrients are affected when the root system deteriorates.

Nutrient Leaching: Leaching of important nutrients from the soil can occur as a result of overwatering. Deficits in nutrients caused by this leaching may impair the general health of the tree.

Reduced Resistance to Stress: Overwatering a tree all the time makes it more vulnerable to stressors like pests, diseases, and extremely high temperatures. Due to its weakened state, the tree is more vulnerable to additional harm since it is less able to withstand these stresses.



The state in which trees or plants do not receive enough water to meet their requirements for healthy growth and development is known as underwatering. It’s a state in which there is insufficient moisture in the soil to sustain the essential processes of the plant.

Reduced Growth: An absence of water hinders a tree’s capacity to carry out photosynthesis and generate energy. A tree may become smaller than it should be for its age and species as a result of inhibited development.

Wilting and Drooping: Trees try to hold onto the moisture they do have when they don’t get enough of it. Trees use this conservation approach to try to decrease water loss through transpiration, which frequently results in withering and drooping leaves or branches.

Leaf Damage and Browning: Stress indicators on underwatered trees might include browned or dried leaf tips and margins. This happens when a tree’s restricted water supply makes it difficult for it to sustain vital processes.

Increased Susceptibility to Pests and Diseases: A lack of water can stress trees, making them more susceptible to insect and disease assaults. A weaker tree is less able to protect itself from insects, fungi, and other undesirable creatures.


How to Ensure Proper Watering

Observe the Soil: Feel the soil with your fingertips to determine its moisture content. Test the soil around the tree with your finger; if it’s dry up to a particular depth (usually a few inches, though this varies depending on the type of tree), it’s time to water.

Tree Type and Age: Watering young trees more often is typically necessary since their root systems are still growing. In general, mature trees need less irrigation.

Climate: Compared to colder, more humid climates, hot, dry areas may need more regular watering.

Soil Type: When it comes to water retention, well-draining sandy soil may need less frequent watering than the latter.

Watering Technique: Use techniques like soaker hoses, slow-drip irrigation, or deep watering at the tree’s base to make sure the water reaches the root zone rather than shallow, frequent watering that only saturates the top.

Seasonal Variations: Adapt the watering schedule to the changing of the seasons. Trees may require more water in the summer or during dry spells, and less in the winter.

Mulching: Mulching the area surrounding the tree’s base can assist in controlling soil temperature and moisture retention.

Achieving a balance in watering is crucial to make sure the trees get enough moisture without becoming overly wet. The best way to determine how much water your trees need is to look at their condition, the state of the soil, and the surrounding environment. If in doubt, seeking advice from a nearby gardener or arborist can offer particular recommendations for your tree species and local circumstances.


When to Water Your Trees

First of all, to prevent evaporation and stress, avoid watering trees in the hottest part of the day, instead water early in the morning and in the evening.

Secondly, a simple test to determine the need for watering can be done by inserting a trowel into the soil about 20 or 25 cm. If the soil feels damp, it is unlikely to need water, but if it is dry, then watering is probably required.

watering a young treeFinally, check for signs of stress or drought, which include:

  • wilted leaves
  • little growth
  • curled or rolled leaves
  • colour change

Generally, trees need water corresponding to about  25 mm of rain per week from June to September. However, avoid over-watering which can also cause stress.

How to Water a Tree Properly

The important thing to remember when watering your trees is to make sure the water is delivered slowly and heavily, so the roots can absorb the water, otherwise it encourages shallow root growth. Shallow roots cannot tolerate drought.

Water around the tree’s drip line (circle on the ground marking the edge of the tree canopy), rather than just around the trunk.

Too much water and roots will drown, too little and they will dry up and die.

Heavy clay soil does not drain well and needs less frequent, but heavier watering.  Lighter, sandy soils need less water applied at a time, but more frequently.

Do Newly Planted Trees Need More Water?

sprinkler on lawn watering treesYes indeed they do! New trees need water to survive and thrive. 

Transplanted trees need water immediately after they have been planted and on a frequent and regular basis after that. Water helps newly planted trees establish roots and recover from being transplanted. These trees should be watered well at least once or twice a week, either with an irrigation bag or a soaker hose. This needs to continue throughout the growing season and for the first 1 or 2 years.

Watering and Established Trees

As a general rule, established trees do not need watering because their roots are wide and deep. Only when it is especially dry and hot or windy, they may need water just to keep healthy and maintain strength and avoid stress. Water helps reduce the risk of disease in trees or the invasion of insects, pests, etc.

Remember, a tree is an investment and a healthy tree is better able to withstand insects, pests and diseases.

Local weather conditions, your soil type and the age of your trees are all factors that determine the amount and frequency of watering needed. The best thing you can do for your trees is to provide the right amount of water at the right time. This will ensure that you grow and maintain vigorous and beautiful trees that benefit you and the environment.

Rely on Ottawa’s Tree Pros at Croft Tree Experts

If you have questions, contact the certified arborists at Croft Tree Experts. We specialize in tree assessment and advice, as well as tree pruning, tree removal, hedges and much more.