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One of the things I struggled with when I first started getting into bonsai was just how much sunlight these miniature trees required. I was living in an apartment at the time and didn’t fully realize the amount of direct sunlight needed to maintain the health of bonsai. So do bonsai trees need sunlight?
Bonsai trees need at least 5-6 hours of direct sunlight every day to maintain optimum health. This is especially true in the warmer spring and summer months, from May to September. Failure to get enough sunlight will result in the weakening and eventual death of your tree.
So what if you keep your bonsai tree indoors – how do you manage the amount of sunlight? And what bonsai tree species need more or less light? Keep reading to find out more!
Just a quick heads up, over the past three years of running Plantpaladin, hundreds of people have asked for product recommendations. As such, You can find my favorite indoor bonsai tree here (link takes you to Bonsaiboy), my favorite outdoor bonsai tree (link takes you to Bonsaiboy), or have a look at all the products I recommend here.
How much sunlight do bonsai trees need?
Bonsai trees can be incredibly temperamental – needing enough water but not too much that you overwater them.
Needing enough pruning but not too much that you damage the tree.
One of the most challenging aspects of keeping bonsai is managing the sunlight levels of bonsai trees.
Luckily I’ve visited a few of my local bonsai garden centers, have managed to keep bonsai successfully both indoor and outdoor for a few years, and even asked 10 plant paladin readers in a recent survey exactly how much sunlight bonsai trees need.
Here are the results:
- Most bonsai trees species need at least 5-6 hours of direct sunlight every day from March to September
- This is because bonsai trees, like all flora, need sunlight for food through the process of photosynthesis.
- During the peak months such as May to August, bonsai trees can need as much as 8 hours of direct sunlight per day to remain healthy.
- Bonsai trees will need even more direct sunlight to maintain their health on the back of battling an insect infestation or fungal outbreak.
- Most bonsai trees then benefit more when kept outdoors where the UV sunlight is direct, intense, and not artificial
- Some bonsai species however can be grown indoors with the help of artificial grow lights such as fluorescent or LED lights
- Bonsai species that are not suitable to be kept indoors, and need more sunlight include non-tropical, temperate trees such as juniper or maple. Some evergreen species such as pine or junipers will also struggle without a lot of sunlight
- Tropical bonsai species tend to work best indoors such as jade or Chinese elm
What bonsai tree species need more light?
All bonsai trees need a lot of sunlight. Temperate bonsai, flowering bonsai, or bonsai that bear fruit such as azaleas, plumb, or lemon will need more light to produce their fruit or flowers. They should be kept in direct sunlight for at least 6 hours per day in the summer.
Now whilst the light needs of your bonsai will vary depending on the species, it’s worth noting that all bonsai trees will need some degree of light.
Luckily I’ve put together a table below with the most common bonsai species beginners tend to own, as well as the best selling bonsai species, and listed the amount of light they require:
|
Bonsai Species |
Amount of light required |
| Chinese Elm | 5-6 hours during the summer |
| Ficus | 4 hours during the summer |
| Juniper | 6 hours of direct sunlight in the summer 4 hours of mild sunlight in winter |
| Maple | 6 to 8 hours in the summer months |
| Jade | 4 to 6 hours during the summer months |
| Fukien Tea | 2 to 3 hours during the summer months |
| Pine | 5 to 6 hours during the summer – larger longer pines require more light |
| Wisteria | 6 to 8 hours in the summer months |
| Azalea | 6 to 8 hours in the summer months |
| Cotoneaster | 4 to 6 hours during the summer months |
| Cherry blossom | 4 to 6 hours during the summer months |
| Lemon | 6 to 8 hours in the summer months |
| Crabapple | 5 to 6 hours during the summer |
| Orange | 5 to 6 hours during the summer |
Now I’ve also come up with a table below using the information above showing if the bonsai species you own can be grown indoors with sunlight from the window or grow lights.
| Bonsai Species | Can you keep indoors? |
| Chinese Elm | Yes |
| Ficus | Yes |
| Juniper | No |
| Maple | No |
| Jade | Yes |
| Fukien Tea | Yes |
| Pine | No |
| Wisteria | No |
| Azalea | No |
| Cotoneaster | No |
| Cherry blossom | No |
| Lemon | No |
| Crabapple | No |
| Orange | No |
What happens if bonsai trees don’t get enough sunlight?
If bonsai trees do not get enough sunlight it will weaken their leaves and foliage. This in turn will interrupt the photosynthesis process, cutting off the food to your bonsai and, if not resolved, will result in the death of your tree.
Lack of light will also cause:
- Higher chance of insect infestation
- Higher chance of fungal or root infections
- Shriveling Branches
- Leaves falling off
Let’s explore these in more detail:
Death
Easily the biggest issue with not getting enough sunlight to your bonsai is that simply put, it can cause the death of your tree.
Sunlight is absorbed through the leaves of all bonsai species and in turn transformed into food during the photosynthesis process.
A lack of sunlight or UV light will mean that your bonsai tree will have no food to do its primary functions.
This means it will not be able to absorb water from the soil in your bonsai pot, be able to remove toxins, and essentially start to shut down and die.
Insect infestations
Believe it or not, some plant and tree species used in bonsai will often have natural chemical defense mechanisms to avoid being overrun by insects.
During the summer months, it is incredibly common for bugs like aphids, whiteflies, and even slugs or birds to attack bonsai trees.
While keeping bonsai indoors will stop this problem it will also weaken your tree due to lack of sunlight, meaning when you move your bonsai back outdoors, your tree’s natural defense against these pests will be weakened.
The best thing to do then is to keep your bonsai tree outdoors so it gets enough sunlight, but also use either a natural insecticide such as neem oil or invest in a good insecticide and check your plant regularly.
Fungal or root infections
Similar to the point above.
A lack of sunlight will also make your bonsai tree more likely to develop issues such as root or fungal infections.
These can usually be spotted through white spots on the leaves of your tree.
Avoid them, by using a good fungicide and keeping your bonsai in prolonged sunlight in the aftermath of any infections to speed up its recovery.
Shriveled branches and falling leaves
As your bonsai tree will not be getting enough sunlight and in turn, food, it will start prioritizing its core functions.
This will often result in things such as secondary or tertiary branches starting to shrivel up and die, leaves of your bonsai turning yellow, or even starting to fall off.
Lack of light will often mean that your bonsai will try to reduce the number of leaves it has to optimize what little light it does have.
What bonsai trees can survive with artificial light?
Bonsai tree species such as Chinese elm, ficus, jade, and Fukien tea can all be grown indoors with artificial UV lights. Other tropical species also work well indoors. These bonsai trees, however, like all others, will benefit more from being kept outdoors with direct sunlight.
I found that for best results, cycle bonsai between indoors and outdoors.
For example, let’s say you are keeping a Fukien tea bonsai tree indoors, I would recommend keeping it inside for no more than 3 days before you move your bonsai outdoors for a few direct hours of sunlight.
You can then move this tree back indoors after a few days.
Leaving your bonsai indoors for too long, regardless of its species will eventually cause it to weaken which is why I find that cycling bonsai is the best thing to do.
What’s even better is that this is relatively easy to do, seeing as though most bonsai trees are not planted in the ground but easy to carry from the pots they are in.
How much light do flowering or fruit bonsai need?
Flowering bonsai or bonsai trees that produce fruit will often have more light requirements than other tree species. These trees then should typically have between 6 and 8 hours of direct sunlight during the summer months.
These trees should also not be kept indoors as they tend to struggle with artificial light conditions.
“Chinese elm and ficus bonsia make the best optins for keeping bonsai trees indoors”
When do bonsai trees typically get less light?
Bonsai trees will typically get less direct sunlight if kept in the shade or indoors. It is important if you keep your bonsai indoors you keep them near an artificial light source or for best results a south-facing window.
How to ensure your bonsai tree gets enough sunlight?
So now we know how much light your bonsai tree needs and why sunlight is so important for bonsai, how can you ensure your bonsai tree gets enough sunlight?
To ensure your bonsai gets enough sunlight, Keep your bonsai outdoors in the brightest spot of your garden for at least 5 to 6 hours during the summer months. Should you keep your bonsai indoors, keep it facing a south-facing window or invest in artificial UV lights to meet its light needs.
Let’s explore these below:
Where should you put your bonsai for the best light?
As mentioned above the best location for your bonsai tree to ensure it gets enough sunlight will depend on the following and if you keep your bonsai indoors or outdoors:
Keep your bonsai in a bright spot
So if you keep your bonsai outdoors then you might think leaving it anywhere in the garden will work fine for it to get enough sunlight.
This isn’t necessarily the case.
You see all plants if kept together will compete for sunlight.
This is often determined by the number of leaves and the size of a bonsai.
The best thing to do then to ensure that your bonsai gets enough sunlight if you keep it outdoors is to keep it at the brightest spot in your garden.
It’s also worth keeping bonsai of the same size near each other.
For example, if you have a medium-sized bonsai and an imperial-sized bonsai, and keep them next to each other – it’s only natural that the larger imperial-sized bonsai will take up the majority of the sunlight.
| Classification | Size inches | Size Centimeters | Hand size | General size |
| Keshitsubo | 1 to 3 inches | 3 to 8 centimeters | Fingertip | Tiny |
| Shito | 2 to 4 inches | 5 to 10 centimeters | One-hand | Tiny |
| Mame | 2 to 6 inches | 5 to 15 centimeters | One-hand | Small |
| Chohin | 5 to 8 inches | 13 to 20 centimeters | One-hand | Small |
| Kumono | 6 to 10 inches | 15 to 25 centimeters | One-hand | Small |
| Katade-mochi | 10 to 18 inches | 25 to 46 centimeters | Two-hand | Medium |
| Chiu or Chumono | 16 to 36 inches | 41 to 91 centimeters | Two-hand | Medium |
| Dai or Omono | 30 to 48 inches | 76 to 122 centimeters | Four-hand | Large |
| Hachi-uye | 40 to 60 inches | 102 to 152 centimeters | Six-hand | Large |
| Imperial | 60 to 80 inches | 152 to 203 centimeters | Eight-hand | Large |
Now if your tree still struggles to get enough sunlight you might want to consider defoliating your bonsai – this will help your tree grow more leaves improving its sunlight absorption.
Use a south-facing window
Should you keep your bonsai indoors, it’s imperative that you also get your tree enough light.
I’ve already talked about cycling your plant between bing kept indoors and outdoors, but if you live in an apartment block or a place where you can’t keep your bonsai outdoors then there are a few things you should do.
First, open the windows and keep your bonsai tree next to the window – this will ensure it gets as much direct light.
You should also aim to keep the windows of your home open to get additional benefits such as airflow to your tree.
Keeping your bonsai indoors will mean that the amount of direct sunlight your tree will get will be filtered through the glass and any curtains or blinds you have.
As such, one of the best things you can do (if possible)is to keep your plants near south-facing windows.
South-facing windows will allow your bonsai to better absorb the sun’s heat and light energy.
This can also help your bonsai should you keep it indoors during the winter months when the amount of sunlight is repeated.
Finally, if your plant is struggling indoors we can use artificial lights which we will cover below.
Do bonsai trees need artificial light?
If you keep your bonsai tree indoors you will need an artificial light source. This is because bonsai trees need a steady flow of 5 to 8 hours of direct sunlight, depending on the plant species during the summer months. For best results use fluorescent, LED, or HID lights.
What artificial lights work best?
So if you are keeping your bonsai indoors – let’s explore the different light options at your disposal to help maximum light absorption for your trees.
Fluorescent lights
Fluorescent lights have been one of the oldest types of lights used to grow many plants indoors.
For best results aim to keep your fluorescent lights 8 to 12 inches away from your tree spending on the size of your bonsai.
These lights will work well on smaller bonsai sizes, from tiny fingertip bonsai to medium-sized bonsai.
Larger six-hand or 8 hand bonsai will not be able to thrive with fluorescent lights.
The best bulbs to use with fluorescent lights are:
- CFL bulbs
- T5 or T8 bulbs
Aim to keep these lights on from 16 to 20 hours per day.
I’d also recommend keeping an eye on your plants if they have a lot of leaves -whilst these lights are fairly weak and don’t give off a lot of heat (meaning you won’t have to worry about dried out soil) I would recommend checking for burned or dried out leaves every few days.
LED Lights
Due to the advancements made in technology, LED lights have become commonplace in the use of indoor plant keeping for the past 15 years to 20 years.
LED lights provide a strong light output, without having to worry about the increased heat damaging or drying out your bonsai soil.
These lights are also relatively inexpensive – meaning if you have a larger indoor bonsai nursery you keep them at a low cost.
A 50 watt LED will work best for most plants (although you may need more depending on the size of your tree).
Aim to keep these lights about 10 to 15 inches away from your tree and your bonsai should be able to thrive.
Most LED lights have intensity control meaning if you need to increase the brightness or light spectrum – you can usually do this.
HID Lights
HID lights whilst commonly used for indoors bonsai do have several disadvantages that the other light sources don’t have.
Firstly these lights and incredibly powerful, often the bonsai trees we keep indoors are not fruit-bearing meaning the amount of light used is often too much for the bonsai we keep.
Second of all, these lights produce a lot of heat, making it very common to burn your trees if not placed correctly.
HID lights can also rack up your energy and electricity bills, often being less efficient than LED lights for example.
The major benefit of using these is they are powerful – if you live in a colder, darker climate and are adamant that you want to grow bonsai then these would work best.
For best results then – keep about 20 to 30 inches away from your bonsai, ensure that you check your plants daily for signs of drying out, and water your bonsai more than you would normally.
Try to ventilate the space you keep your bonsai in too to manage and create better airflow 0 using a bonsai pot with a lot of drainage holes can also help.
How much sunlight is too much sunlight for bonsai?
Bonsai trees typically need 5 to 8 hours of direct sunlight during the summer months. Longer prolonged exposure to sunlight can cause the soil of your tree to dry out, cause your leaves to burn, and impact your bonsai trees’ overall health.
Typically then, if you live in a warm climate at the peak of summer, leaving your bonsai in the sunlight for more than 8 hours will be dangerous to the health of your tree.
Shade and bonsai
If you do find that you have a sunnier warmer spring/summer than normal, one of the best things you can do is keep your bonsai in the shade.
For best results, keep your bonsai in direct sunlight during the sunniest part of the days for the recommended times we talked about in the table above.
Then once this time has been completed move your tree in the shade for the remainder of the day to avoid any issues in your tree drying out.
This method will also work particularly well if you have kept your bonsai in for a long time.
If you are moving your bonsai from indoors to outdoors, start by placing your bonsai in the shade for the first week or two.
Then ease it into a mix of direct sunlight and shade for another week.
Finally, you can keep your bonsai in direct sunlight.
This works very well for things like bonsai seedlings or growing your bonsai from cuttings.
Do larger bonsai trees need more sunlight?
Larger four-hand, six-hand, or eight-hand bonsai will need more sunlight than their fingertip, one-hand, or two-hand bonsai. The larger a bonsai gets, the more sunlight it needs to maintain and continue its growth.
Do bonsai trees need sunlight in winter?
Bonsai tree species that are deciduous and go dormant during the winter will not need sunlight during the winter months. Evergreen bonsai species such as pine or junipers will need some sun during the winter but not direct sunlight and so can be kept in the shade.
For all bonsai trees, during the winter, extra work will be required to best prepare them for the next growing season.
To help with this I would recommend checking out my posts below:
- How to build a bonsai cold frame
- How to winterize your bonsai
Countries with the most sunlight
Now a lot of you reading this will be doing so from around the world so I thought I would make a list of both the sunniest and least sunny countries in the world.
This will determine if you need to invest in any artificial light to grow your bonsai.
Countries with the most sunlight per year
| Country | Hours of sunlight per year |
| United States | 4015 |
| Egypt | 3863 |
| Sudan | 3814 |
| Chad | 3792 |
| South Africa | 3732 |
Countries with the least sunlight per year
| Country | Hours of sunlight per year |
| Columbia | 637 |
| Faroe Islands | 640 |
| China | 954.8 |
| Russia | 1164.3 |
| Equatorial Guinea | 1176.7 |
Do Chinese elm bonsai need sunlight?
Chinese Elm bonsai need 5-6 hours of direct sunlight daily during the summer months to maintain its health. These should be kept in the brightest spot outdoors to thrive. Chinese elm bonsai can be kept indoors but should be placed near a window or kept with artificial light.
Do jade bonsai need sunlight
Jade bonsai need 4-6 hours of direct sunlight daily during the summer months to maintain its health. Jade bonsai can be kept indoors, due to it being a succulent tropical tree species, but should be placed near a window or kept with artificial light.
Do juniper bonsai need sunlight
Juniper bonsai needs 6 hours of direct sunlight daily during the summer months. They will also need 4 hours of mild sunlight in the winter as it is an evergreen species. Juniper bonsai should not be kept outdoors. Place in the brightest spot in your garden for best results.
Do ficus bonsai need sunlight?
Ficus bonsai need only 4 hours of direct sunlight during the summer and little to no sunlight during the winter. These bonsai then are the perfect bonsai species to be kept indoors, reacting favorably to both artificial and direct sunlight.
Do evergreen bonsai need sunlight
Evergreen bonsai species such as pine or cedar need at least 6 hours of direct sunlight during the summer. These bonsai also require 4 hours of indirect sunlight during the winter. Evergreen species with longer needles will require more light. Evergreen bonsai should not be kept indoors.
Study on how much sunlight bonsai trees need?
So I didn’t want to just give you my experience on how much light bonsai trees need.
As such I visited my local botanical gardens and asked one of the staff about bonsai light needs, here is what they said.
“Bonsai trees usually need more light than other types of trees and plants. Usually between 4 to 8 hours per day during the summer. I’d also avoid keeping bonsai indoors and they can develop health issues”.
I also surveyed 10 plant paladin readers and here were the results:
My top picks for the gear you will need!
So like I mentioned earlier, over the past three years of running PlantPaladin, hundreds of people have asked me for my recommendations on the best bonsai gear on the market.
Having spent thousands of dollars on bonsai items these past few years and tested at least 100 bonsai-specific products, I’ve listed my favorite products below – All of which I highly recommend and think you can get great value.
They can purchase directly by clicking the link to take them to Amazon.
Bonsai Tool Set: One of the significant challenges I’ve had is finding a toolset that was not only durable but didn’t break the bank. SOLIGT has recently developed a fantastic bonsai tool set that covers all the tools you need to trim, prune, and repot your trees. – You can grab it here.
Complete Bonsai Set: Many of you will want to grow your bonsai trees entirely from scratch, but finding the varicose seeds, pots, and other items in one place can be challenging. Leaves and Sole then have created a complete bonsai set that I’ve personally used that ticks all the boxes. You can grab it here.
Bonsai wire: The number of times I’ve run out of wire for my bonsai or purchased cheap bonsai wire that doesn’t do the job is embarrassing for me to admit. After a lot of trial and error, I found that using Hotop’s aluminum bonsai wire is one of the best options on the market. This can easily be used for both indoor and outdoor bonsai. You can grab it here.
This post was written by Fehed Nicass who has been passionate about bonsai for over 3 years.
