How to Keep a Bonsai Tree Alive (Indoors or Outdoors)

To master the art of bonsai, one must be disciplined. Not only for the plant, but also to maintain the entire spirit and philosophy of the practice.

Soon, your bonsai tree will become a reflection of your inner spirit. Then, it will become a chunk of your personality, possibly contributing to the best parts about it. 

It should come as no surprise, then, that approaching bonsai in the right way is pivotal to the art, which is why we created this thorough guide on how to keep a bonsai tree alive and thriving.  

Are Bonsai Trees Easy to Care for? 

Contrary to popular belief, anyone, even you, can easily grow bonsai plants at home with the proper care insight. 

Bonsai newbies often panic before starting their bonsai journey, immediately conjuring up stereotypes like, “only a Japanese gardening master can grow a bonsai, as it requires a great deal of skill, decades of experience, and endless amounts of patience.”

While the art of bonsai is undoubtedly challenging, it’s a skill that can be practiced by even a beginner gardener. All you have to do is align the basics and leave the rest to the forces of mother nature. 

Indoor Bonsai Trees vs. Outdoor Bonsai Trees

Before we jump onto mastering the art of bonsai, you need to understand the general types of bonsai to prevent any leafy calamities in the future. 

One of the most common questions from new bonsai enthusiasts is, “what’s the difference between indoor and outdoor bonsai?” 

Luckily for you, it’s not that difficult to grasp. 

Indoor bonsai trees are temperate trees belonging to subtropical species. Since the subtropical climate is relatively stable, an indoor environment works best for your precious tropical bonsai tree as it is not directly exposed to the elements. 

Here are a few popular examples of indoor bonsai trees:  

• Chinese Elm 
• Ficus bonsai trees 
• Jade bonsai trees

Outdoor bonsai trees are the tough cookies. They can survive all weather conditions, which is why they are also called evergreen trees. But, these cold hardy trees can also benefit from a rest period during the winter months, so consider bringing them inside when their leaves begin to fall.

Some of the most beloved outdoor deciduous trees for bonsai include: 

• Juniper bonsai 
• Maple bonsai 
• Japanese Black Pine bonsai 

You can choose to grow your bonsai as per your liking, whether it is indoors or outdoors, as many pro bonsai gardeners have dwarfed their outdoor plants to conform to indoor conditions. 

How Do You Keep an Indoor Bonsai Tree Alive?  

For the best care of a bonsai, it is vital for you to execute the following factors precisely. It all comes down to choosing and sticking to what works best for your bonsai. 

Light  

Light has paramount importance when growing bonsai. Since an indoor setting has a lower light intensity, striking the right lighting balance with enough light for healthy growth is necessary for achieving the optimal light intensity for your bonsai. 

We, as humans, need oxygen to survive. Similarly, bonsai plants need light to grow. If proper light is not provided, a bonsai tree’s growth will gradually decline or stop, causing its leaves to fall and staggering production. 

Still, not all species of trees, full-form or bonsai, need the same amount of light to thrive. A tree grown with bonsai will need similar lighting conditions to its full-sized counterpart, so be sure to research what that is. 

If you are still unsure about its needs after your research, placing your bonsai in a bright spot with direct light would be a good idea to start, as bonsai trees have less foliage to photosynthesize with and will need more sun to thrive. The ideal spot for direct light throughout the day is in a south-facing window (for the northern hemisphere). 

Keep an eye on your bonsai tree to see how it responds to any changes in placement or light exposure. You can almost always figure out what it likes or doesn’t like in a short span. Sometimes, light from a window is not enough. If you see a lack of growth, you can easily add a grow light into your lighting mix. 

Just ensure that your grow light is fluorescent and has growth-friendly spectra suitable for your bonsai species. 

Temperature 

Typically, bonsai trees can stand tropical temperatures or those of an indoor environment. Since tropical temperatures aren’t too far off from typical indoor temperatures, you can keep most bonsai indoors all year long. 

Subtropical temperatures are below their tropical counterparts. This means a subtropical type of tree enjoys a relatively lower temperature and tends to thrive in cold weather, which is ideal for outdoor bonsai. While cold-hardy bonsai trees can brave the harsh low temperatures of the outdoors throughout the winter months, be mindful of shifting them indoors during their dormancy periods. 

Water

This might sound strange, but never opt to follow a strict and regular watering regime for your bonsai tree. Watering becomes subjective with so many soil types and bonsai species, so you should take a more calculated approach when watering your bonsai trees. 

It’s a great idea to only water your bonsai tree whenever the topsoil appears dry. A moisture meter can help you decide with certainty when it’s time to water your bonsai. You don’t need a water meter, though. If the soil is dry a few inches under the surface, you should water soon.   

You need to immerse the roots in water, so watering until you see droplets dripping down the drainage hole at the bottom of the pot is a good idea.

Potted Exotics Pro Tip: Water your soil in slow bursts, providing about 10 seconds between pours to let the water filter and reach lower levels. Doing this will ensure that even the very center of the soil in the pot will receive moisture. Pouring water too fast can lead to dry patches throughout the soil. 

Overwatering will kill your bonsai tree quicker than you can say ‘bonsai.’ Overwatering causes your roots to get drenched in too much water, preventing oxygen from reaching them and stunting growth and production.

Underwatering, on the other hand, is the most common cause of bonsai tree deaths. If you give less water to your plant than is needed, your plant will succumb to dehydration. These small trees have small containers, meaning water is already extremely scarce. This goes for both indoor and outdoor bonsai types. 

Humidity

The humidity level often goes unnoticed by beginners; it is one of the most critical factors governing a bonsai tree’s growth. Tropical indoor trees belong to the tropics, as the name suggests. The tropical climate is characterized by high humidity. 

On the contrary, our homes have rather low humidity levels thanks to air conditioning and heating. 

So, to combat the humidity problem, say hello to the humidity tray – one of the best inventions in the gardening world. The operation is simple: place your bonsai on the humidity tray filled with water, and voila! 

Soil

An exemplary soil mixture should possess proper drainage, water retention, and aeration. 

Efficient drainage can be achieved by adding large particles to your soil mixture. These range from volcanic rocks to small pebbles/stones. The large particles will create pockets of volume underneath your soil surface, creating prominent aeration; your roots need all the oxygenation they can get. 

Potted Exotics Pro Tip: If you are having trouble with soil water retention, consider adding vermiculite, sphagnum/peat moss, or coconut coir to your potting mix. These materials help maintain soil porosity while also enhancing water retention. 

Drainage is the most decisive trait of a brilliant soil mixture. If your soil’s drainage is not on point, your plant may suffer from excess water in the root system (which can lead to fungal infections and root rot) and an overall lack of growth. 

Bonsai Tree Growth Rate 

It doesn’t take a botanist to realize that the best plant growth occurs during the seasons of early spring and early summer. But there’s a catch. 

Your beloved babies are cramped in small pots, restricted from growing horizontally. Unlike free vegetation, a bonsai plant’s root system can not roam freely and suck up nutrients from wherever it likes. To compensate for this, you must fertilize your bonsai soil in abundance during the growing season. 

Here is a simplified growth rate guide that covers almost all bonsai species, which can help you determine your fertilizer application rate throughout the year.  

Season	Growth Rate
Early Spring to Early Summer	Highest (fertilizer for the win)
Late Summer	Declines
Fall	Stabilizes
Winter	Dormant

Pruning Bonsai Plants  

Pruning is an essential element of the art form of bonsai; without it, the tradition of bonsai would not have existed. It is widely regarded as the most intricate part of growing bonsai trees. Pruning is necessary for providing a bonsai tree with its revered shape, and apart from aesthetics, it helps a great deal with growth as well. 

There are two types of pruning, which we discuss with you now. 

Maintenance Pruning 

Maintenance pruning has unparalleled benefits for your bonsai tree’s shape and growth. When you prune away young branches, leaves, buds, and shoots, you expose the inner layer of new leaves to fresh sunlight and oxygen. This encourages the plant to boost its new growth rate and health. 

The regular pruning of branches allows you to dictate the shape and direction of growth of your tree. When you prune away your tree’s leaves and branches, the upcoming ones are always better, more resilient, and healthier. Maintenance pruning is to be done whenever your bonsai tree looks untidy and unpleasant. 

Potted Exotics Pro Tip: Practice your pruning skills on an outdoor tree before lopping off the ends of your precious bonsai. 

Structural Pruning 

Structural pruning is focused on the tree’s aesthetic shape. It is a specialized form of pruning that comes naturally to very few. The rest of us have to practice and learn. 

Disclaimer: Structural pruning should only be conducted when the tree is dormant.

With structural pruning, you can either remove the tree’s main branches and dictate the new ones’ direction of growth. You can also use wiring to control the shape and direction of growth of select branches. Wiring is undertaken by wrapping a small thin wire around the branches. 

Common Problems with Bonsai Tree Care 

Root Rot 

Root rot describes a root infection caused by a pathogen. Typically, root rot is bound to appear in overly damp root systems or roots that have spent a prolonged time in soggy soils.

There are two types of root rot: 

• Healthy Root Rot: You shouldn’t worry about this as this is a natural phenomenon of your bonsai tree’s growth. This type of root rot is caused by the rootball’s own fungi and bacteria that are non-pathogenic in nature. Healthy root rot is easy to detect and differentiate from invasive root rot. 

If you repot your tree and see dead roots, it’s natural, as roots often die down when their respective branches are pruned away. If your bonsai tree appears healthy, then the root rot you see is caused by non-pathogenic bacteria and fungi. 

• Pathogenic Root Rot: Pathogenic root rot targets living roots. As living roots are compromised, they are unable to transport vital nutrients and water to the foliage above. Eventually, the foliage dies. 

Reasons for pathogenic root rot include overwatering, uncovered wounds from pruning, cold temperatures, and dampness. Avoid such mistakes while tending to your bonsai tree for best results. You can look out for this detrimental root rot by checking for the yellowing of leaves and discoloration of foliage. 

Spider Mites and Other Pests 

Spider mites, snails, and other pests are not uncommon when growing bonsai trees, but when a tree’s health is compromised, they become a plague. You can deal with these types of pests by using neem oil or a pest spray. We advise using neem oil, as it is organic, safe to apply, and effective as a treatment. 

Dead Branches 

Dead bonsai branches can be a sign of several issues, including root rot, under-watering, under-fertilizing, and a lack of oxygenation. The best way to deal with dead branches is to prune them before an infection builds up. 

Yellow Leaves 

Yellowing bonsai leaves can be a sign of overwatering, under-watering, and overexposure to light. This can easily be dealt with by dealing with the problems mentioned above. 

Spotted Leaves 

Spotting on your bonsai leaves is an alarming situation. If you see dark reddish and brownish spots all over your leaves, there is a high chance that your bonsai tree has caught a fungal infection. To treat your bonsai, prune all the leaves containing these spots. Next, go to your nearest gardening store and get yourself an anti-fungal medicine, and apply as recommended.

How to Repot a Bonsai Tree 

Since a bonsai pot is tiny compared to a larger pot, which is used for potting garden plants, they require a close eye and careful preparation for repotting. 

The important thing to know is that dead roots and organic matter will soon clutter the small pot. The clutter will starve the plant’s root system, reducing its ability to absorb nutrients and water. The best solution to this inevitable issue is to repot your bonsai every 2 to 5 years. 

Here is a step-by-step guide on repotting a bonsai tree. 

1. Steadily lift your bonsai tree from its pot. 
2. Carefully shake away and remove any stale, old, or compact soil around the root ball.
3. Remove dead roots if you find any using shears. 
4. Inspect the root system for rot. If you find a rotten patch, carefully remove it. 
5. Thoroughly wash the pot. 
6. After covering the drainage holes with mesh, carefully add a layer of soil at the pot’s bottom before repotting your bonsai. 
7. Fill soil in empty patches. 
8. Water in your bonsai

Different Types of Bonsai Trees to Grow at Home

Chinese Elm Bonsai Tree

The Chinese Elm is a hardy type of bonsai tree. It is immensely expendable, being able to thrive in both outdoor and indoor environments. You can even keep it outdoors during the winter season. Contrary to popular belief, you don’t have to water your Chinese Elm on a regular basis. The indoor version of the Chinese Elm is best suited to lower temperatures. 

Juniper Bonsai Tree 

The Juniper tree species is a diehard outdoor plant. It simply does not survive well indoors, although you can bring it to indoor protection if temperatures drop below 15°F. Water with caution, as junipers do not like soggy or consistently moist soil.

Ficus Bonsai Tree 

Ficus trees love sunlight, but they actually prefer indoor environments. You can keep yours outside if temperatures do not drop below 65°F. Although they do not like hot weather and cold months, their special needs only include an abundance of light. For the healthy growth of your bonsai, make sure that you water your ficus tree only when the surface of the soil appears dry. This will help achieve healthy roots and optimal nutrient uptake

Japanese Maple Bonsai Tree 

The first thing to know about Japanese Maple bonsai trees is their love for the outdoors, especially in arid and sunny locations. However, if temperatures rise above 85°F, it is time to shift them indoors for the sake of their fresh soil. Their shallow tray requires plenty of watering in the summer months, so you may have to water your tree daily during the growing season, as these bad boys tend to soak water up pretty quick. 

Pine Bonsai Tree 

Pine trees love to be outside, especially during their two bouts of growth. Since Pine bonsai trees dislike permanent moisture, make sure you do not overwater them. 

Fukien Tea Bonsai Tree 

Naturally, Fukien Tea bonsai trees love the indoors due to their temperateness. They are vastly biased towards the light, which means you will have to keep them right beside a window. You will also have to regulate their temperature to around 75°F. The top of the soil needs to be kept moist at all times, but do not make the mistake of overwatering your Fukien Tea. 

Hawaiian Umbrella Bonsai Tree 

The Hawaiian Umbrella species will never be a hassle, as these bonsai trees love the indoors, moderate temperatures, and dim lighting. If you want smaller leaves and healthier growth, it is a good idea to increase light exposure. These bonsai trees like their soil moist. 

Chinese Sweet Plum Bonsai Tree 

You can either keep your Chinese Sweet Plum indoors beside a window or outdoors in a semi-shaded location. This tree species needs protection from harsh sunlight, however. Since the whole tree can wither easily due to a lack of water, keep its root system moist at all times. 

How to Keep a Bonsai Tree Alive FAQ