Imagine this common scenario in relation to watering bonsai trees: An excited shopper spent the day at a bountifully stocked garden center and quickly fell in love with the bonsai trees. After carefully examining the many beautiful specimenover waters on display, they picked their favorite and brought it home.
With enthusiasm, they read the care instructions on the label, and it says to water the tree every single day in the evening. Sadly, many bonsai labels misinform their owners in this way. So what is the truth about watering bonsai trees?
In reality, how often a bonsai tree should be watered in order to thrive depends on a number of factors. Careful observation is a skill that all bonsai owners must cultivate, and things like the tree’s size and species, the time of year, and the climate will all play a part in guiding your watering schedule. Today we’re going to break down everything you need to know about watering bonsai trees so that yours can remain at its absolute best.
The Big Question: How Often Should I Water My Bonsai?
While it would be very convenient to have a fixed schedule for watering your beloved bonsai tree, there is no one-size-fits all formula. Instead, as bonsai growers we must learn to carefully look each day for the signs that it is time to water, and always ensure that our bonsai trees are never overwatered or—absolutely crucially—underwatered.
Both of these mistakes can lead to a bonsai tree becoming weak and unhealthy, although underwatering bonsai trees can become life-threatening very quickly, making it imperative that the responsibility of watering bonsai trees is never left to a negligent neighbor or disengaged family member!
We will come back to planning trips away when caring for a bonsai tree later, but for now, let’s examine what to look for when deciding if it is time to water your bonsai tree.
Signs That It Is Time to Water Your Bonsai Tree
The key to watering bonsai trees is to do so only when the soil is beginning to dry out, but before it dries out completely. You can check how moist the soil is in your bonsai tree’s pot by inserting a finger to about a quarter-inch (one centimeter) depth to see how dry the soil is. If the soil is no longer damp and is beginning to feel dry, then watering time has arrived.
Over time and with experience, you will learn to assess whether your bonsai tree needs to be watered by visual inspection alone. Some bonsai growers invest in a moisture meter to check the soil’s dampness, although it is possible to manage perfectly well without one.
Never Let Your Bonsai Tree Dry Out Completely
When it comes to the mistakes that cause bonsai trees to become sick or even die, the most common error is inadequate watering. Whether this comes in the form of forgetting to water the tree completely, neglecting to increase watering when the weather becomes hot and dry, or not understanding how to water properly, there is no doubt that too little water is a very big threat to your beautiful bonsai specimen.
Correctly watering bonsai trees is all about balance. You need to view your commitment to checking on your tree each day in the same way that you do brushing your teeth—when it becomes part of your daily routine, it will become far easier to ensure that your bonsai tree goes only from strength to strength.
When to Water Your Bonsai Tree
Now that you know the signs that indicate that your bonsai tree should be watered, you might be wondering if there is a certain time of day that this task is best undertaken.
Many experts advise watering preferentially in the morning and evening, because during the hottest part of the day, evaporation will be at its highest and much of that precious water may be lost before your tree gets the chance to absorb it.
Some other bonsai experts suggest that the temperature contrast created by using cold water when the tree’s roots are warm may cause a shock, although this idea remains debated. Crucially, despite these considerations, you should always water your bonsai immediately if it is beginning to get dry.
When the weather is hot or your central heating blasting, it may become necessary to do this twice a day. Even air conditioning can be very drying for your bonsai—making efforts to increase humidity essential, which we will return to in a moment. Watering reactively depending on circumstances and ultimately the dampness of the soil in your bonsai tree’s pot is always the very best tactic.
How to Water Your Bonsai Tree Correctly
When you can see that the soil is no longer wet and is in fact becoming slightly dry, it is time to water your bonsai tree. To give your tree the good drink that it needs, it is essential to soak the entire root system.
The best approach to achieving this is to water from above, using a flow that will not wash the soil away. Continue to apply water until it runs out of the holes at the bottom of the bonsai pot. When you see this, pause for ten seconds and then repeat the process. Doing this three times will allow you to be absolutely certain that your bonsai has been adequately watered.
Another approach is to submerge the entire bonsai pot in a sink or container of water for a short while before returning it to its usual home. Bonsai tree roots do not like to be submerged for long, so never leave your tree in a tray or container that keeps the roots sitting in water for hours.
The Importance of the Correct Soil Mix for Bonsai
Bonsai trees are grown in a special type of soil that helps to ensure that the roots of the tree get just the right amount of moisture—not too much, and not too little. Bonsai substrate also ensures that the tree’s roots always receive enough oxygen.
This unique soil type is a mixture of organic and inorganic ingredients that provide just the right conditions for bonsai tree roots to thrive. In contrast, regular soil will most likely get too water-logged and not allow enough aeration for your tree to remain strong and vibrant.
When bonsai trees become pot-bound, this can also limit their ability to absorb enough water. If you identify that your bonsai tree needs to be repotted, always buy—or even make—a well balanced bonsai substrate to ensure that watering your bonsai tree will remain effective.
Achieving The Perfect Humidity for Bonsai Trees
Out in the natural world, the tree species that we use to create spectacular bonsai trees live in very different conditions from those found in our homes and workplaces. More often than not, our indoor spaces are far dryer than a bonsai tree would prefer, so we need to actively increase the humidity around them to help them stay happy and healthy.
The watering and humidity needs of bonsai trees can be seen as two different things, because while watering should only be done when necessary, humidity should be maintained all the time. So, how exactly do we achieve this?
One of the most simple tools to harness is a humidity tray for bonsai trees. Placing your bonsai’s pot over a tray of water—without allowing the water level to rise above the bottom of the pot—will ensure that the air around your tree is always humid. In fact, many bonsai pots come with a matching tray. Lots of bonsai experts place pebbles in the tray to slow down how quickly the water will evaporate.
Another great tactic for helping your bonsai tree remain humid is to use a spray bottle to mist your tree several times each day. Misting bonsai trees will help the leaves stay clean and bright while increasing local humidity overall. If your home is heated or air-conditioned, opening a window to allow damper air in from outside may also be useful, but be careful of cold drafts that might damage your bonsai tree.
Asking Others to Water Your Bonsai Tree
Because of the specific needs of bonsai trees when it comes to watering, their care does require some forethought whenever we go away on holiday or business. Asking a distracted teenager or busy dog sitter to bonsai-sit can be a risky endeavor!
So, if you know you are going away for a few days or longer, either seek out someone you know you can trust and give them very clear instructions, or explore alternative approaches to watering bonsai trees.
Inviting someone who will care for your bonsai tree to water it with you once before you leave will help them get things right. Otherwise, there are automatic bonsai watering systems on the market, but these do tend to be quite expensive. Another tip to consider is setting your thermostat before you go to ensure that your bonsai tree does not get too cold or warm in your absence.
Watering Bonsai Trees With Confidence
So there you have it—you are now in the know on watering bonsai trees like a true expert! Of course, you can expand that knowledge even further by researching the bonsai tree species that you choose to keep.
Different types of bonsai trees can have slightly different requirements. For example, the Jade Tree can handle drying out a little more from time to time, while the Fukien Tea or Carmona Tree will be far less forgiving!
One of the beautiful things about keeping bonsai trees is that the ritual of caring for them every single day teaches us so much about discipline and the rewards of dedication. The pride that comes with tending successfully to a bonsai tree for many years cannot be beaten. To enjoy this achievement yourself, be sure to visit us here at Keeping Bonsai for the latest guidance and insights on all things bonsai.