Things To Avoid When Growing Bonsai Trees

Growing bonsai trees is not easy, yet it can be fun and challenging at the same time. However, there are things that some growers miss doing or things they do that can result to sickness or death of their bonsai trees. In this tutorial, we will discuss the most common problems bonsai growers face and the solution for them. We will be covering the following topics:

  1. Watering Issues: Underwatering and Overwatering
  2. Bonsai Trees Planted in the Wrong Environment
  3. Using the Wrong Type of Soil
  4. Not Feeding or Using Fertilizer
  5. Choosing the Wrong Bonsai Pot
  6. Over Pruning Bonsai Trees
  7. Bonsai Not Getting Enough Sunlight
  8. Using the Wrong Bonsai Tools

1) Watering Issues: Underwatering and Overwatering

Watering is considered one of the most important skills when it comes to growing a healthy bonsai tree. In fact, bonsai experts may take years to learn watering bonsai trees the right way. Bonsai trees need water to thrive, without water, your bonsai tree will die, and this is an irrefutable fact.

Bonsai novice growers often have no difficulty in understanding this. But one can easily forget or ignore the fact that excess water can easily kill a bonsai tree like no water at all. That is why it is important to understand the role of water in bonsai trees for a more successful bonsai growing.

Bonsai leaves use water and nutrients to obtain energy from the sun and the atmosphere through photosynthesis to form organic molecules like sugars needed to build and grow leaves, stems, branches, roots, and trunk.

Understanding the Role of Water

Almost 55% to 85% water make up the bonsai tree’s weight. Water does not only help with the translocation of nutrients, but it also helps with its overall turgidity. In leaves and stems, the percentage of water is from 70% to 90%. The first signs of underwatering or water scarcity include dropping leaves and stem. In fact, prolonged water scarcity can also affect photosynthesis.

Water enters the bonsai tree through the young roots, in the area behind the root tips, through the hundreds of fine root hairs, greatly increasing the surface area when exposed to water in the compost soil. This will make it easier for the water to enter the root system through the fine membrane through the process called as “osmosis”. It refers to the movement of water from areas of higher concentration toward lower concentration areas through very fine membranes. Root hairs are only short-lived and they’re being replaced constantly.

Once the water is inside the root tips, it is moved through supporting cells into the xylem, which is a water transporting vessel. These are narrow, long, and hollow tubes without living matter and are joined from end to end, providing a continuous pathway from the bonsai roots through the stems and to the leaves. The water moves from the xylem, root tips and toward the leaf tips. Any excess water is lost to the atmosphere via transpiration which is regulated by stomata or the little window-like cells. Stomata open and close in response to carbon build up and temperature in the leaf. Almost 98% of the water is taken in by the roots and then transpired from the surface of the leaves.


One of most common reasons why bonsai trees die is because they’re underwatered. These bonsai trees are placed in very shallow containers allowing drainage of water continuously. The tendency is water will be completely dispersed out onto the ground after a day. If they’re not watered correctly, these bonsai trees will die. To water a bonsai tree, bonsai gardeners need a fine water nozzle. Avoid any strong spray because it can wash away the soil in the container or pot, thus exposing the roots.


If bonsai trees are left too wet, they get saturated and are at a higher risk of developing root rot and mold and mildew infestation. You can prevent overwatering by checking the soil moisture or dryness using different methods such as the finger method, the chopsticks method, lifting method, and using a moisture meter.

How to Use a Moisture Meter

A moisture meter comes handy to help you in measuring the humidity in the soil, thus preventing overwatering and underwatering of your bonsai trees. Moisture meters have a scale of 1 to 10, with results as 1 being the driest and 10 being the wettest. Most moisture meters also have a color range that is composed of red, blue, and green. Investing in a reliable moisture meter is a good idea so you can check the soil moisture instantly.

Step-by-Step Guide in Using a Moisture Meter

Step #1: Choose a device. A moisture meter may come as plain or fancy. It can check not only moisture, but also soil acidity, light, soil, and other factors. You can use a plain moisture meter for quick checking of soil moisture. Choose a moisture meter that instantly measures and doesn’t require batteries.

Step #2: Hold the gauge end or head of the moisture meter. The probe is the pointed end. Simply insert the probe deep into the soil or three-quarters deep down into the bonsai pot. This will help measure the soil moisture in the bonsai roots.

Step #3: Entering the red zone. Some bonsai trees need dry soil because there are species that can easily be killed by overwatering, so the soil moisture should be in the red zone or low. There are bonsai tree species that require moderately humid soil such as azaleas and ficus, so their soil humidity must be in the green zone. If the moisture meter is in the red, the bonsai tree is ready for watering. If the moisture meter is in the blue zone, it means that the soil is too wet. Don’t water again until its roots show green or red.

Tip:Monitor regularly

Use the moisture meter to spot-check your bonsai trees. Never leave the moisture meter in the bonsai tree pot for too long. You need to wipe off the probe of your moisture meter after using, and keep it dry and properly cleaned.


You don’t want to overwater or underwater your bonsai plants, so checking the soil before watering is very important. Instead of relying on guesswork, it is best to invest in a device like a moisture meter to ensure you obtain accurate results and water your bonsai plants as needed.

2) Bonsai Trees Planted in the Wrong Environment

People usually have an unfortunate tendency to treat bonsai trees like any other house plants. However, these bonsai trees should not be treated as houseplants because they’re trees and they should be treated that way. It is important to ensure that you mimic the natural environment of the original tree where your bonsai tree was obtained from. For most bonsai tree species, they do better when they are placed on the patio rather than inside the house. Whatever area they’re put in, it should always mimic the natural environment the native tree is in.

Temperature and Humidity Greatly Affect Your Bonsai Trees

All indoor bonsai trees during winter should be kept warm but not too hot. The right temperatures should range from 50 to 70 degrees Fahrenheit. Remember though that, this temperature range is not applicable for all bonsai tree species. Bonsai gardeners should base the right temperature on the tree’s origin.

While indoor bonsai trees need to live in a standard room temperature,  bonsai tropical trees survive in places where room temperatures are properly maintained for the entire year because they can’t withstand the freezing cold of the winter season. During winter, these bonsai tree species shouldn’t be placed near open windows or in cold places.

Tropical bonsai tree species are best kept in warm temperatures all year round. These bonsai trees grow without a dormancy period and they prefer temperatures between 64 and 75 degrees Fahrenheit at daytime and 57 to 61 degrees Fahrenheit at nighttime. This is the normal indoor temperature during the winter season. You need to avoid cold bonsai roots, wherein the roots are colder as compared to the indoor environment. You need to make sure that your bonsai trees are located near a heat source to prevent lose moisture and keep humidity levels at the proper range.

Subtropical and Mediterranean bonsai trees can sustain cooler temperatures better even in the very cold winter months. Non-tropical bonsai trees need this type of temperature in order to survive. You can place your bonsai trees in cool window ledge or cold room. You can place your sub-tropical bonsai trees outside but be sure you protect them against drafts.

When it comes to humidity, this is a very important consideration. It is best to buy humidity trays with a bag of pebbles to increase humidity for your bonsai tree. Humidity trays also help protect your table surface or desk where the bonsai pot is placed.

Maintaining the Temperature of Bonsai Roots

Bonsai roots are delicate and sensitive to temperature changes. You need to ensure that your bonsai trees don’t get too dry during summer and not too cold during winter. In spring, the first thing you need to do is to trim your bonsai tree.  Trim your bonsai in the shade so root ball doesn’t get dry due because of sun exposure.  You need to always carry a water spray bottle to moisten the roots whenever they appear dry.

Managing the temperature is crucial during the summer. The placement of your bonsai tree will depend on their native origin. Tropical bonsai trees should be placed in warmer environments while temperate bonsai species should be placed in full shade or in a partly shaded spot. Temperate species are sensitive to extremes of temperatures.  Tropical tree species can die from very high temperatures. In fact, they’re more likely to be harmed by heat as compared to others.

Monitor the Temperature of Your Bonsai Tree

You need to be attentive to different changes in temperature, monitoring even the slightest changes to make sure your bonsai grows as you expect it to. You may use a thermostat on the wall to control the room temperature or use a thermometer. Investing in these devices are can help you check the temperatures in smaller spaces. Place these devices in areas close to your bonsai trees, providing the actual temperature of the environment.

How to Avoid Temperature Fluctuation

When it comes to indoor temperature, it is greatly affected by the presence of heating systems, oscillating and exhaust fans, breezy hallways, and windows. Bonsai trees are very sensitive to sudden changes in temperature. A sudden and drastic spike or drop in temperature may injure your bonsai tree. You shouldn’t keep any indoor bonsai tree near the open door or window in order to protect them against drafts.


Just because many species of bonsai trees are grown outside naturally doesn’t mean they should be left outdoors all year. Your bonsai tree may need to be brought inside because temperatures change. During the winter season or summer, these can be too much for your bonsai tree. It is important to know what your bonsai tree requires and ensure make sure it is placed in a good environment that is suitable for it as close to its natural environment as possible.

3) Using the Wrong Type of Soil

Bonsai trees don’t grow in regular plant potting soil. They need constant drainage. If they’re put in a regular potting soil, their roots will rot and won’t drain properly. The best qualities of a bonsai soil should be gravely and loose. The correct bonsai soil should be placed in the bonsai pot if the new soil needs to be added. Many bonsai growers put their bonsai trees in the wrong soil and are wondering why their bonsai trees die.

Bonsai trees don’t do good in just any type of plant soil. Your ultimate goal is to find a bonsai soil that drains water quickly but still has the ability to retain water. It should contain small particles for proper aeration and to allow oxygen to reach the bonsai roots. You’ll find specialty soil commercially available on the market made specifically for bonsai trees. You can also choose to mix your own. It’s imperative adding fertilizer to your bonsai soil during the growing season most especially early springtime to mid-fall.

4) Not Feeding or Using Fertilizer

Fertilizing or feeding a bonsai tree is crucial during the growth period. While normal trees can extend their root system to search for nutrients, bonsai trees are planted in small pots and they need to be fertilized to replenish the nutritional content of the soil.

Basic Parts of a Fertilizer

There are three basic macronutrients needed by bonsai trees which include nitrogen, phosphorus, and potassium or the NPK ratio. Every element serves different purposes. For example, nitrogen helps in increasing the growth of leaves, branches, and stems of bonsai trees above the ground. For healthy roots, phosphorus is required, which also promoted growth and development of flowers and fruits. Potassium promotes the overall health of bonsai trees. Different NPK ratios are used for different bonsai tree species at different times of the year.

Best Time to Apply Fertilizer to Your Bonsai

During the entire growth period of your bonsai tree, it should be fertilized from early spring until mid-autumn. More mature or older bonsai trees are fertilized less frequently. Feeding highly depends on the bonsai tree species, time of year, the health of your bonsai tree, and the stage of development. Indoor bonsai trees can be fertilized all year round. Don’t fertilize repotted bonsai trees for about a month.

Never fertilize sick bonsai trees. It can aggravate their condition and even leading to nutrient burn since they are not able to utilize the nutrients properly like they would normally do when they’re healthy.

5) Choosing the Wrong Bonsai Pot

Many bonsai growers most especially beginners, choose the wrong size of bonsai pots. Choosing a bonsai pot is one of the first activities you need to do when setting up a bonsai. You cannot just use any pot or any container as a bonsai pot. There are also important factors to consider when choosing the right size, shape, and even color of bonsai pots for your bonsai trees.

General Guidelines When Choosing a Bonsai Pot

Guideline #1: If you are choosing a  bonsai pot for your bonsai tree, choose one that is large enough for the roots to also stretch a little bit. The tips of bonsai roots play a crucial role in the proper absorption of water and nutrients, so it is important to have enough room for them to draw these from the soil quickly and easily.

Guideline #2: Regardless if you want to repot your bonsai tree in a larger bonsai pot or just keep it in the similar size it’s currently using, you need to take into consideration the age of your bonsai  tree, the presence of rootbound, bonsai tree species, and whether you like your bonsai tree to still grow bigger or just stay in its current size.

Guideline #3: Re-potting your bonsai doesn’t necessarily mean that you must increase the size of the bonsai pot. Although there are different types of bonsai pots for sale in the market today, it is important to take into consideration your bonsai tree’s needs and your own preferences. Established bonsai trees can retain their same pot size because you can already perform regular root pruning whenever you repot.

Guideline #4: Bear in mind that the bigger the bonsai pot is, the longer it will go and survive between watering sessions. In times of low humidity and too much heat, you need to buy bonsai pots that are slightly larger than the average container.

Guideline #5: The ideal length of a bonsai pot should be around 2/3 the height of your bonsai tree. If ever the height of your bonsai tree is shorter than the width, the length of the bonsai pot should be at least 2/3 the width of the spread. Its width should be slightly narrower as compared to its spread or longest branches, which applies on both sides.

6) Over Pruning Bonsai Trees

At some point, you need to prune your bonsai tree to get it into its right shape. With proper pruning, you can accelerate your bonsai tree’s growth, shaping it according to your preference, thus making it aesthetically pleasing. Pruning will help expose the inner branches of your bonsai tree to get extra sunlight. Pruning your bonsai tree too much may affect its ability to absorb sunlight and make nutrients.

When it comes to pruning, you avoid using scissors. You can use clippers to remove dead branches. Deciding which branches to remove will help in maintaining the desired design of your bonsai tree. Pruning a bonsai is considered as an art.

7) Bonsai Not Getting Enough Sunlight

If you place your bonsai tree inside the house, it will not receive an adequate amount of sunlight. The sunlight actually helps your bonsai trees to produce food via photosynthesis and grow healthily. It is important for your bonsai tree to obtain enough hours of exposure to sunlight, otherwise, it may wilt, become unhealthy, and die. But remember that too much sunlight exposure may produce the same effects. It is important to look up for the specific requirements of the bonsai tree species, making sure that it’s getting its ideal amount of sunlight.

Your bonsai tree brings a peaceful and natural feel to any living space. Because a bonsai tree is not technically an ordinary plant, but a real tree, it is a truly enchanting and unique addition to any room or your outdoor space. Make sure it will get plenty of direct exposure to sunlight. You can place it either outdoors or indoors near your window.

8) Using the Wrong Bonsai Tools

If you use the wrong tools when caring for your bonsai, it can actually cause severe damage to your bonsai tree. The main tool used by bonsai growers when dealing with bonsai trees is a good pair of bonsai scissors. This is not the same as regular scissors that are sharpened with flat surfaces. Bonsai scissors are specifically made in cutting branches and wires without crushing your bonsai tree. If a regular or standard pair of scissors is used to work on your bonsai tree, it will just crush and eventually damage your bonsai tree.

The other tools required include wire cutters, wire pliers, and branch cutters. As your bonsai tree requires to have its older and sturdier branches trimmed, its branches will need trimming or cutting off using branch cutters. You also need wire pliers and wire cutters that are specifically designed for caring bonsai trees. As your bonsai tree is shaped towards its ultimate form, the bonsai tools will be more complex and increasingly vital.

Materials and Tools for Maintenance

For removing dirt and rust on the blades of tools, you can buy rust erasers such as Clean Mate, and different types of grindstones can be used for sharpening the blades. When it comes to sharpening blades, it requires a bit practice and it’s a good idea to start practicing on old and worthless shears first before your actual bonsai tools.

It is important to disinfect your bonsai tools every now and then. This will help in preventing fungi, virus, or bacterial infections from being transferred from one bonsai tree to another. Camellia oil and gun oil are suitable for the proper maintenance of blades and hinges. Coco brushes can be used for sweeping bonsai trunks, soil surfaces, tables, shelves, tools, and Nebaris.

Final Words

There are still so many things that many bonsai growers do on their bonsai trees that should be avoided. It is the result of ignorance and no experience. But with this tutorial, you have learned the basic things you need to avoid when growing your bonsai tree. We hope that you learned a lot and you can share this information with your family and friends. You may want to also share your thoughts and insights by posting a comment below. We highly appreciate you for taking the time to read this tutorial Happy bonsai growing everyone!