The Ultimate Guide To Watering Your Bonsai Tree

Understanding how much water your bonsai tree needs is one of the most important skills you will develop as a bonsai gardener. Without water, there is no life. The fastest way to kill a bonsai tree is to let it completely dry out. It takes time to learn your tree’s needs but eventually, watering your bonsai will become second nature. Properly watering your bonsai is a skill on its own. It’s not as straightforward as beginners would expect. It’s not uncommon to learn proper watering technique through trial-and-error aka killing a few bonsai trees.   

Watering a bonsai tree is not difficult, different than watering a common houseplant. Bonsai trees have small, restricted root systems so they need to be watered more frequently. Because the tree is confined in a container, a bonsai loses its ability to self-regulate its exposure to moisture. Beginners often make the mistake of over- or under-watering their trees. If you purchased your bonsai tree, it should have come with a detailed care guide with the recommended watering procedure. Your tree will need a continuous source of moisture or you will have fatal results.

Enthusiasts have come to find that watering a bonsai tree is more of an art than a science. There are no hard rules about watering a bonsai because there are too many variables. On top of that, every tree has different watering requirements. It becomes an art as you observe the tree and understand when (and when not) to water it. Many factors affect how and when to water your plant. You’ll need to consider and understand all of these factors before you lift your watering can.

In this article, we’ll provide an in-depth understanding of how to properly water bonsai trees and the methods to help your bonsai be successful and thrive.

How Often Should I Water My Bonsai Tree?

Bonsai trees dry out more rapidly than the common houseplant due to their course soil and shallow pots. Two different bonsai trees can have two completely different watering needs. There are many factors to consider when determining how often you should water your bonsai tree. Read the next section in this article to learn about each of these factors. Expect to spend a few weeks observing and becoming familiar with your tree and its watering needs.

Bonsai trees should not have a routine watering schedule. Daily watering without understanding the conditions of the soil can result in over- or under-watering. You should only water your tree when the soil is slightly dry. As you gain more experience, you’ll be able to see when your bonsai tree is slightly dry without having to feel the soil.

The rate at which the soil in a shallow pot dries out depends on many factors like the time of the year, humidity, soil composition, and tree variety. During the summer months, you could be watering your tree twice a day, while in the colder months you could be watering a lot less.

How Much Water Do Bonsai Trees Need?

The best way to know how much water your bonsai tree needs is to feel the soil. There are several factors to consider when determining how often you will need to water your tree. Over time, you’ll understand your tree’s needs by simply observing the foliage and the weight of the container. The lighter the plant, the dryer it is.

As a beginner, you can figure out if your tree needs water by feeling the soil. Continue reading to learn about the different methods used to determine the soil moisture level.     

Here are some factors that affect how often you will water your bonsai tree.

Soil Mixture

Having the proper soil mixture is essential for the survival of bonsai trees. It’s important to consider the component ratios in your soil mixture. The main components on bonsai soil include clay, peat moss, and vermiculite. These components retain water and if your soil mixture contains a high ratio of these materials, you’ll increase the soil’s holding capacity. This may decrease how often you need to water your tree.

Be careful adding more of these components to your current soil mixture. If the volume is over 25% you decrease aeration and drainage and risk the potential of root rot.

If you want to increase aeration and drainage, you’ll want to add larger components to your soil mixture. Some great options include coarse sand, lava rock, perlite, and various clay products.

Fertilizer

Fertilizer is mixed with soil to provide essential nutrients that promote growth and health. While fertilizer is a necessary component for a bonsai’s survival, it also accelerates the soil’s drying time. Fertilizers speed up the decomposition of the soil’s organic components. As a result, fertilizer can slow down the growth of your tree.   

To prevent this, be sure to use a high-quality organic material as well as a firm inorganic material, such as wood like pine.

Plant Size

The size of your bonsai tree affects how often you need to water it. If your bonsai is a larger, fast-growing tree, it can dry out the soil quickly.

It’s normal for certain bonsais to dry out their soil quickly, but that also means you must frequently water it. If you are growing an outdoor bonsai tree, you will want to water it daily without overwatering.  If you have a miniature-sized bonsai, you will also need to water often and potentially use a humidity tray.

For more information on bonsai plant sizes, check out our bonsai sizing chart.

Container Size

The size of your bonsai container determines how much water your tree retains. Bonsai grow in small, shallow pots. The bigger the container, the more soil you can use. The additional soil volume increases water retention and keeps the soil moist for a longer time. If your bonsai tree is fast-growing, consider putting it in a bigger container.

Sunlight

Sun exposure will heat your tree and its container which results in evaporation of any stored water. If your tree is exposed to a lot of direct sunlight, expect to water it frequently. Your bonsai will grow rapidly in direct sunlight. To slow down the growth, relocate your tree so it receives some shaded area. Ideally, you’ll want to place your tree in a location where it gets direct sun in the morning and shade in the afternoon.   

Weather Conditions

Wind and humidity impact how quickly the soil dries.

Strong winds can dry out your bonsai trees and makes them vulnerable. It’s good practice to protect your tree from the elements. Keep your bonsai tree away from areas that receive frequent gusts of wind. This is especially a problem during the winter. If you don’t properly winterize your bonsai tree, you risk the soil freezing. If the soil is frozen, roots cannot properly absorb water and the stems lose water. Protect your tree through continuous watering in the colder months.

Bonsai trees thrive with higher humidity. It’s important to increase humidity levels to extend a bonsai’s watering cycle. This is especially necessary for hot, dry climates.

Diseases

Bonsai trees are vulnerable to various diseases if not properly maintained. Root rot decreases the ability to intake water and slows down the dry time. Continue reading this article to learn more about root rot and its signs.  

watering a bonsai tree

How Do I Check The Soil Moisture Of My Bonsai Tree?

Your bonsai tree’s soil must never become fully dry. You must check the soil on daily to understand when it’s time to water your plant. There are several methods for checking the soil moisture of your bonsai.

Soil Moisture Meter

The most accurate way to determine the soil moisture level is by using a handy tool called a soil moisture meter. A moisture meter is a valuable tool that takes the guesswork out of your watering. A moisture meter measures the moisture of the soil near the root.

Whether you are a beginner or professional, this tool is extremely valuable because it prevents bonsai trees from being over- or under-watered. Although there are variations between models, the scale typically ranges from 1 to 10 (or dry to wet).

Using a moisture meter is simple. Here are the steps:

  1. Insert the probe into the soil until it reaches the root level.
  2. Note the moisture level on the scale.
  3. If the soil’s reading is “moist” or “dry”, water your bonsai tree. For bonsai trees, you’ll want to water it when the moisture level is at level “3”.
  4. Remove the probe from the soil.
  5. Clean the meter after each use.

Many gardening enthusiasts love the XLUX T10 Soil Moisture Sensor Meter because of its simplicity and accuracy. The long probe and large scale make it easy for any gardener to determine the soil moisture of their plant.

The Finger Method

If you don’t have a moisture meter, the finger method is an easy way to check your soil. Put your finger about one inch deep into the soil. If you don’t feel too much moisture in the soil, it’s likely time to water your tree. This is a general rule that does not apply to all bonsai trees. If you have a succulent bonsai, like a Jade, it thrives on a dry period. Be sure to research your bonsai type.

The finger method is an acceptable way to check for soil moisture, but it’s not accurate. It can be difficult to gauge if the soil is most with just your fingers. This is especially true when it’s cold.

The Chopstick Method

Another way to check the moisture level of your tree’s soil is by using the Chopstick Method. For this method, you will need a plain, wooden chopstick (not stained or treated wood) or any other kind of wooden stick (like a popsicle stick).

  1. Put the chopstick 1-2 inches deep into the soil. Be careful not to damage any roots. You will want the bottom of the chopstick to be about halfway between your tree and the rim of your pot.
  2. Leave the chopstick in the soil for 10 minutes. This gives the stick enough time to absorb any water in the soil.
  3. Remove the chopstick and check it. If the chopstick is darker or has a watermark, then the soil is moist- there is no need to water your bonsai tree at that time. If you notice a slight color change, the soil is partially moist and you should recheck it in a day. If you see no color changes, then the soil is dry. It’s the perfect time to water your bonsai.
  4. Clean the chopstick and let it dry. It can be used on the same bonsai tree for another moisture check in the future.

The chopstick method allows you to check the moisture level of multiple plants at the same time. However, be sure to use a different chopstick for every plant to avoid cross-contamination of fungus or other diseases.

What Kind Of Water Should I Give My Bonsai Tree?

In most cases, a gardener can use tap water to hydrate bonsai trees. Use water that you would personally drink.  

Before using the water from your sink, check to see if your water is hard using a water quality tester. Other indicators that you have hard water include dry itchy skin, spots on your dishes, soap scum around the sink, or mineral buildup around your fixtures. 

Hard tap water is still acceptable for watering a bonsai. Although it is beneficial to occasionally collect and use rainwater. Using rainwater is not essential, but it helps remove any salt build-up in the soil. Store rainwater in the appropriate pottery for future use. 

If your water has a lot of chlorine, let it sit in your watering can overnight. The chlorine will evaporate and your bonsai will have cleaner water.

Signs of Under-Watering A Bonsai Tree

Under-watering is the most common way to kill a bonsai tree. A bonsai’s soil dries up significantly quicker than other plants because it is homed in a small, shallow container. To thrive, bonsai trees need a continuous flow of water. Like other plants, these trees need water to release essential nutrients. Without enough water, the tree’s structure will collapse and dry out. Because they are in containers, bonsai trees lose the ability to regulate moisture exposure.

A bonsai’s root system depends on water to grow. Check for leaf loss, soil, moisture and overall health of the bonsai to determine if your tree is under-watered. There are several immediate signs of an under-watered bonsai tree.

  • Yellowing leaves
  • Brown or drying leaves
  • Dry Soil

If you find that your bonsai tree is under-watered, you will need to use the immersion watering method. See the immersion watering method below to learn how to use it. The immersion method is a quick fix for dry bonsai trees, but it should not be used frequently. If a bonsai is exposed to too much water, you risk root rot.

Can You Overwater A Bonsai Tree?

Overwatering is a big threat to bonsai trees. Many beginners are so concerned about drying out their trees that they accidentally overwater them! Giving your tree too much water can kill them. It can take years to learn the art of properly watering a bonsai tree. In the meantime, use the tips in this article to know when it’s time to water your tree.  

It can be difficult to see the effects of overwatering. For many beginners, it can take a long time before they understand that they have been overwatering their bonsai.

If you are checking your tree’s soil every day and find that it is always wet, it could be a sign that you are overwatering. The soil should not be constantly wet. Roots need oxygen to “breathe” and the excess water reduces the soil’s ability to absorb air.

Signs that you are overwatering your bonsai tree are:

  • Leaves turn yellow and eventually fall off
  • The trunk begins to look unstable
  • Branches become small and weak
  • The stems die

If you are overwatering your bonsai tree, do the following.

  1. Remove your bonsai tree from its container.
  2. Check the roots to ensure they are healthy. Healthy roots are white and firm. Too much water and a lack of airflow can cause roots to decay. If your roots are brown, mushy, or have a foul odor, remove as much of the rotted root as possible.
  3. Cut off any yellowing or dying leaves. If you previously removed a large number of roots, it is beneficial to cut off a similar portion of the tree’s top growth. This puts less stress on the bonsai as it recovers.
  4. Rinse your entire tree and prepare a container. It’s best to use a new, clean container. If you choose to reuse your old container, you need to clean and disinfect it to remove any traces of the infection. Scrubbing the container with hot water and detergent is the best method.
  5. Water your tree with cold chamomile tea. Chamomile tea is a natural antifungal that can be prepared at home. You can use tea bags or even powdered tea.
  6. Give your tree sunlight. Position your bonsai in a brightly lit area, but now in direct sun.
  7. Water sparingly. Resume watering your bonsai. Be sure to avoid overwatering by checking the soil’s moisture level.

Root Rot

The roots will die and then begin to rot. Root rot occurs when microorganisms colonize the dead tissues. If the soil remains wet, the bacteria can easily spread throughout the root system. The roots become smaller and your tree becomes unstable. Eventually, the tree will die. Root rot is typically a result of poor-draining soil that is wet and lacks air.

Gardeners will typically detect root rot when they are repotting their trees. Rotted bonsai roots are black and crumble when touched. If you come across root rot, cut off the dead areas to prevent it from spreading.

watering a bonsai tree

Bonsai Watering Methods

Bonsai gardeners use several watering methods to ensure that their trees stay hydrated and the soil remains moist. Watering tools are not a necessity, but highly recommended to ensure soil is receiving the proper amount of water and foliage is protected. When watering bonsai trees, it’s important to follow old Japanese practice. Your watering method should mimic a natural rain shower. Bonsais thrive in those conditions.

The two major bonsai watering methods are overhead and immersion.

What Bonsai Watering Tools Do I Need?

There are two basic watering tools for bonsai trees: a watering can and a garden wand.

Watering Can

Owning a bonsai watering can is one of the best investments you can make as a gardener. A quality watering can is the difference between making watering a joy or a pain. You can collect and store rainwater in a watering can. Using rainwater is ideal because there are no added chemicals in the water. However, if rainwater is not readily available, tap water is fine. There are a few major differences between a regular watering can and the ones dedicated to bonsai trees.

Spout Length

Bonsai watering cans have longer spouts so you can easily reach the soil without impacting the foliage.

Spout Shape

The spout, known as a brass rose spout or rosette, lightly showers water. The brass rose spout closely replicates the natural rain shower that bonsai trees are accustomed to.

Many bonsai enthusiasts flock to the Haws Watering Cans because of their colorful designs and exceptional quality. Their long, curved spouts and water flow control make them ideal for watering bonsai trees. Its small size makes it gentle enough to not wash away the soil in your bonsai container.

Garden Wand

Bonsai garden wands provide a gentle shower over your bonsai mimicking natural rainfall. Look for a garden wand specifically designed for bonsai trees. The standard wands found in stores tend to be too large and produce a strong shower that will wash away your bonsai’s soil.

Wands are best for those who care for multiple bonsai trees. It’s an efficient way to quickly water all their plants. The wands are gentle enough to soak soil without washing it away.

Garden Hose

You can use a garden hose to water your bonsai trees as long as you keep it on a low-pressure setting. The mist setting typically works well. You can fit your standard garden house with a gentle spout that will replicate a light rain shower. Remember, if you water your trees with too much pressure, you risk losing all of your soil in the container.

Bonsai Watering: Overhead Watering Method

Overhead watering is the most common way to water a bonsai tree. When using this method, gardeners are using a fine nozzle, a watering can, garden wand, or hose, and gently shower water over your tree. If the water flow is too strong, you risk damaging your bonsai’s trunk and branches. Using watering tools targeted for bonsai trees, like those listed above, prevent potential damage from occurring.

When using the overhead watering method, be careful not to disrupt the soil surface too much. If that happens, you may need to add additional soil. Many gardeners recommend using cold water. Begin watering until you see water coming out of the drainage holes. A humidity tray will catch any water that drips and it protects your furniture.

To water a bonsai using the overhead method, see the following steps:

  1. Check the soil moisture. Determine if the soil is slightly dry. If it is, you can water your tree. See the soil section above for multiple ways to test your soil’s moisture.
  2. Choose your watering tool. You can use a watering can, garden wand, or hose to water your bonsai tree. Be sure that you choose a tool that is dedicated to bonsai trees. Your tool should offer a soft rain shower that mimics nature.
  3. Water your bonsai. Begin watering your tree from the top. Be careful not to wash away the soil. If you see the water creating a puddle on the top of the soil, stop watering and allow it to soak in. Once it’s socked, continue watering tree until you see water coming from the container’s drainage holes. This ensures that the entire root system is wet.
  4. (Optional) Repeat. Depending on your environment, you may need to repeat the process to ensure proper hydration.

Growing a bonsai tree is an ancient Japanese art. It’s important to consider old practice when caring for bonsai trees. One practice involves a watering technique that simulates natural rainfall by letting the water soak in the soil for 15 to 20 minutes and then repeat.

Bonsai Watering: Immersion Method

Another way to water bonsai trees is through immersion. If you’ve been under-watering your tree and the soil is completely dry, water immersion is a quick way to hydrate the roots. This method is very popular for indoor trees because it is effective and budget-friendly.

To water your bonsai with the immersion method, follow these steps:

  1. Fill your sink or a bucket with water. The water should reach about one inch up the trunk of your tree.
  2. Submerge your tree in the water. You will see bubbles as you dunk your tree. Pay attention to how much bubbles are present. A lot of bubbles is an indication that your tree is very dry and needs a lot of moisture. Over time, you will recognize if you are over- or under-watering.
  3. Keep your bonsai in the water until the bubbles have stopped. This may take up to a few minutes. When the bubbles have subsided, the roots are fully hydrated.
  4. Remove the tree and allow it to drain. Check to see if you lost any soil or rocks during the process. Have extra supplies on hand in case you need to replace anything.

Although immersion is a great way to quickly hydrate a bonsai, frequent water immersion is not recommended. Immersing a tree in water too much can cause root damage. If you find that you are regularly immersing your tree because it is continually dry, there may be a couple of issues. One possibility is that it may be time to repot your bonsai. Another possibility is that your tree may need to be placed in a different soil mix that is fast draining and coarse. 

Misting

Bonsai trees require a certain level of humidity which may be difficult to find indoors. This is especially true during the winter when central heating dries out the air and moisture. Misting your tree creates humidity. Misting is a great way to clean foliage and keeps the leaves free of dust Misting also keeps the breathing holes, also known as leaf stomata, open. Misting creates a temporary humid environment. Misting is not required for maintaining a bonsai, although certain varieties, like juniper, thrive on daily misting. Choose a mister that is gentle on your bonsai like the Haws Water Mister.

Misting Does Not Replace Watering

Misting creates humidity and refreshes foliage, but it should never replace regular watering to keep the soil moist. More than likely, the mist will only sock the top layer of the soil and never reach the roots. When misting, quickly spray the foliage, but do not drench your tree.

If you don’t mist your bonsai, humidity tray will increase moisture around your tree. Put your bonsai on a tray filled with pebbles and water. The tray should be a little larger than your bonsai container. As you regularly water your bonsai, the water evaporates and creates humidity around your tree. The stones are not only visually appealing, but they also raise your bonsai above the sitting water to prevent root rot.

Watering Multiple Bonsai Trees At Once

If you have to water multiple bonsai trees, you may consider investing in an automated watering system. These systems are costly, but save you time and ensures that all of your trees are properly hydrated. Automated watering systems typically come with a timer so your bonsai trees can receive water whether you are home or not.

For serious bonsai gardeners, there are timed overhead sprinkler systems compared to ones you would find in a nursery. This system is ideal for professionals who are running a business. You can run your water system as many times as needed depending on the season. 

There is a drawback to using automated watering systems. They may break down and if you don’t check on your bonsai trees every day, you risk killing them.

When Is The Best Time Of Day To Water A Bonsai Tree?

Bonsai gardeners still debate on what is the best time of the day to water their trees. As you can imagine, everyone has a different answer, but the general principles are the same.

Not During The Hottest Time Of The Day

The hottest time of the day is typically in early to mid-afternoon. Gardeners agree that bonsai trees should not be watered when they are exposed to full sun. Watch the moisture level during the dry, hot months. Because the tree is in a shallow container, it’s easy for the soil to dry up quickly. On certain days, you may need to give your trees a second drink It’s recommended that gardeners check on their bonsais twice a day during the summer months for this reason.

Be careful when watering your bonsai in the full sun and avoid splashing water on the foliage. This can potentially burn the leaves.

Watering In The Morning or Evening?

Many gardeners agree that the best time to water your tree is in the morning before it gets too hot. Watering in the morning allows your tree to

Some gardeners recommended watering your bonsai in the late afternoon or evening instead. By watering your bonsai at the end of the day, your soil will remain moist all night and morning.

As you can see, every gardener has their watering time preference, but what does that mean for you?

In the end, you need to water your tree as soon as the soil gets slightly dry. It doesn’t matter if you choose to water your bonsai in the morning or the evening. If your soil is dry in the hot afternoon, you will need to water your tree twice that day.  Always inspect your tree, ideally in the morning and in the evening to ensure you catch your soil before it is completely dry.  

To ensure success, be sure to work bonsai care around your personal schedule. Many of us are away from our home during the day so we may not be able to check the soil in the afternoon. It’s important to observe your tree and get to know its patterns. If you find that your tree dries out by the time you get home in the evening, you should water it in the morning before you leave.

What Is The Best Watering Schedule For My Bonsai?

Bonsai trees should not be on a routine watering schedule. Observe each bonsai tree until you understand their patterns. Daily watering may not be necessary if the soil is still wet. Only water your tree if the soil feels slightly dry. Use the methods listed above to check for the soil’s moisture level.

You must water your tree before the soil is completely dried out. As you progress, you’ll be able to see when your tree needs water without having to check the soil moisture. Remember, many factors will affect how often you need to water your bonsai trees. Follow these guidelines to keep your tree thriving.

Final Thoughts

If you made it through this article, I think it’s safe to say that you understand the importance of properly watering your bonsai plants. Bonsai trees need water to survive, but their watering needs are different compared to other plants. There is no concrete routine that a gardener can follow. How often you water your tree depends on the bonsai species among other factors.

A bonsai tree should never have dry soil. There are several methods to test the soil moisture level so you know when to water it. The most accurate way is using a moisture meter, although you can also check the soil with your finger or a wooden stick. As you gain more experience, you’ll be able to see when a bonsai tree has low soil moisture instead of having to feel for it. For example, you can tell if a bonsai tree is dry by simply lifting it and knowing the weight of the tree and its container.

Beginners often make the mistake of over- or under-watering their trees. Diagnosing an under-watered tree is easy because the signs are evident and appear quickly. It can be harder to diagnose overwatering and it may take beginners a long time before they reach the conclusion.

There is no right or wrong time of the day to water your plant. There are several watering methods to ensure that your tree receives the moisture it needs. If the weather is particularly hot, you may need to water your tree twice a day. Using a watering can, you can use the overhead method until you see water coming out of the drain holes. If you find your tree to be particularly dry, you may opt for the immersion method. However, using the immersion method too often can result in root rot so use it sparingly. If you have to use the immersion method often, it may be time to repot your tree.

I hope this guide provided you the in-depth knowledge of watering a bonsai tree. If you have any questions, leave a comment below!

watering a bonsai tree

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