We often get the question “how often should I water my tree?” or “how do I know if my tree is getting enough water?”

Click HERE for a practical and printable PDF that you can put on your fridge and share with your neighbours!

Watering plays a critical role in maintaining the health and resilience of your tree. Note that there is no exact science here. And while no two trees are the same and their watering needs likely differ dramatically, we’d like to share our watering best practices and insights. As always, be sure to get in touch if you’d like a detailed, free on-site assessment from one of our ISA-certified arborists. First off, how do I tell if my tree needs water? 

Trees have their own ways of communicating with us if you know where to look. Be sure to read up on Tree Care in Drought for additional signs of tree stress in heat/drought. Practically speaking, we offer this test: find a 12” long screwdriver (or similar length of tool) and insert it into the soil at the drip line (see the PDF printout above for where the drip line of a tree is). If it slides in easily and has tiny clumps of moist soil attached to it, your tree doesn’t need watering. But if the soil is rock hard and powdery dry, its time to water!

Step 1: Volume - Determine watering needs

Grab your tape measure, rope or tailoring tape and measure the diameter (which is the circumference of the trunk divided by 3.14) of your tree’s trunk. You can take the measurement at chest height. A good rule of thumb is 1-2 gallons (or ~5.5 litres) of water for every centimetre of trunk diameter. So, if your tree’s trunk has a diameter of 20 centimetres, you’re looking at 30 gallons or ~110 litres of water. Basically, the bigger the tree, the more water it needs!

Step 2: Location - Determine where you need to water

Create your watering zone around the tree’s drip line. This is where the majority of the tree’s feeder roots are located. Watering in this zone targets the areas where the tree needs it most for optimal absorption. 

Step 3: Frequency - Determine how often you should water 

The answer here is “it depends.” Generally speaking, watering your tree once or twice a week is a good rule of thumb. That said, consider a few additional variables (remember when we said this wasn’t an exact science?):

• Age of Tree - A newly planted tree benefits from more frequent watering. Daily or every other day watering is helpful for newly planted trees. After a few weeks, weekly watering is sufficient. The goal is to provide the tree with the necessary water and nutrients to withstand harsh conditions and give it the best chance of growing into a strong, mature tree! 
• Time of Year - More frequent (twice a week) watering during times of drought, heat or dry weather is warranted. 

Step 4: Pace - Slower is Better 

Imagine a slow, steady rain shower – that’s the spirit of how you should water your trees. Don’t just dump a barrel of water in the watering zone of your tree. Maximizing water uptake involves watering over a “long” period of time. How long? We use a rule of thumb of tree diameter (in inches) x 5 minutes = total watering time. So, if you’ve got a 4-inch diameter tree, you’re looking at ~20 minutes of total watering time.

We recommend using a slow soaker hose. You can find one on Amazon, at Wal-Mart or at Canadian Tire. The goal is moist, not soggy. Tree roots need to breathe and if the soil is too saturated, the roots can suffocate and die due to root rot. If the soil is soggy, stop watering and let the soil dry out. Be sure to use your 12” soil probe to monitor the rate of water uptake and make adjustments accordingly.

What time of day is the ideal time to water a tree? 

Water your trees early in the morning or late in the evening when temperatures are cooler. This reduces water loss through evaporation and ensures that the soil retains moisture for longer, benefiting the tree's uptake.

More dos and don'ts of tree watering

Do

• Use mulch. Mulch is the unsung hero in the world of tree care. Apply a layer of organic mulch around the base of your trees to conserve soil moisture, suppress weeds, and regulate soil temperature. Mulching mimics the natural forest floor, creating an ideal environment for tree roots.
• Monitor soil moisture. Regularly check the soil's moisture content by digging a few inches below the surface. Adjust your watering schedule based on your findings to maintain the ideal moisture balance. Again, dry and powdery means your tree needs water. Moist soil around the drip line is ideal.

Don't

• Over water. Over watering can lead to root rot, which can be just as harmful to your tree as too little water.
• Be impatient. Don’t just dump your tree’s required water into the root zone. Go slow and deep - like a few hours of rain!

Educate and empower

Tree watering is not an exact science. It requires experimentation, testing, observing and monitoring. These are our best practices, but you may find your own! And be sure to share your tree watering wisdom with neighbors and fellow tree enthusiasts. Print off, post or share our Tree Watering Best Practices Guide with your friends and family – it looks good on your fridge, shed or garage!