While most bonsai trees do best when kept outdoors year-round, this isn’t an option in most locations unless you have weather that mimics the bonsai’s natural environment. When you have to bring bonsai inside during harsh winter weather, the trees can begin to suffer from lack of sunlight.
Unless you have a species that can handle indoor light levels or have a sunny location in your home that receives plenty of direct light, you may need to use grow lights to supplement the amount of light your bonsai tree receives.
Keep reading to find out the best grow lights for bonsai trees and how to use grow lights properly.
When to Use a Grow Light for Your Bonsai
Grow lights are necessary when you can’t provide enough light for your bonsai to thrive indoors. Some bonsai don’t need extra light during the winter, especially trees that normally go dormant during the winter. However, trees that continue growing over the winter will need more light.
If you don’t have windows that provide a good amount of natural light for these bonsai trees, then you’ll likely need to use grow lights. Bonsai trees that usually grow in a tropical environment tend to need more light, so even if you have a good amount of natural light, you may still need to supplement the natural light if the daylight hours get too short during the winter.
What Type of Grow Light for Bonsai?
There are several different things to consider when it comes to selecting a grow light for bonsai. Part of the selection process should take into account the species of bonsai tree that you have. Different types of trees thrive under different conditions.
There are three types of lights that are generally considered the best to use for bonsai: fluorescent, LED, and HID—all of which have different advantages and disadvantages. Let’s dive in so you can decide which kind of light will work best for your bonsai.
Fluorescent Grow Lights
Fluorescent grow lights are the classic choice for artificial light for indoor plants. People have been using them to keep indoor plants thriving since the 1930s, and they are effective.
Fluorescent lights are easy to find and relatively cheap. They provide a wide spectrum of light that helps bonsai grow in all different stages from seedlings to mature bonsai. Fluorescent lights don’t put off too much heat, so you don’t have to worry as much about burning the leaves on your bonsai. This makes fluorescent lights great for small spaces because they can be placed as close as 2 inches away from plants that don’t have sensitive leaves.
However, there are a few disadvantages to using fluorescent lights for bonsai. The light that spectrum fluorescent lights provide isn’t ideal for flowering or for fruiting unless you specifically buy a bulb that provides dual-spectrum light. These lights also only produce a small amount of supplemental light compared to other options, and it’s not enough light if you are growing multiple bonsai or large bonsai. Fluorescent bulbs are only effective within a range of about 10 inches from a bonsai.
HID Grow Lights
HID grow lights produce the most amount of light for indoor bonsai. They are great for bonsai with lots of foliage and for fruiting bonsai.
Besides producing a lot of light, HID grow lights most closely mimic sunlight. They are so powerful that they can be used in greenhouses if needed. HID grow lights are also cheaper than LED lights although not quite as cheap as fluorescent.
There are a few concerns that keep HID from being perfect for all bonsai, though. Unlike other types of grow lights, HID lights get hot, so they need to be kept far enough away from bonsai so that the tree doesn’t burn. HID are not energy-efficient, so they cost more to run than other grow lights. It can also be difficult to find the right size of HID lights because they are not used as often in the home environment.
LED Grow Lights
LED grow lights have become increasingly popular, partially because they are so energy-efficient and easy to find.
LEDs are a great choice for several reasons. Aside from being energy-efficient, these lights also last a long time. They don’t produce much heat, which means there’s little risk of burning your bonsai’s leaves. Unlike regular fluorescent bulbs, LEDs provide full-spectrum light, meaning they work just as well for bonsai that are flowering or fruiting.
There are a few downsides to using LED grow lights. Even though LEDs are energy-efficient and last a long time, they are more expensive to purchase to begin with. You’ll also need to buy several LED lights because they don’t provide large amounts of light. The light they do produce can be tiring for your eyes as well; if your grow lights are set up in a room you’ll be in often, the blue light from LEDs can strain your eyes.
Grow Light Bulb for Bonsai
Besides the type of light, there are a few more things to take into account when deciding on the best grow light for your bonsai trees.
Lumen
Lumens are the amount of visible light produced. In general, most bonsai will require somewhere between 2,000 and 4,000 lumens to thrive indoors. However, the lumens do not have to come from a single source to be effective; you can use multiple bulbs to provide enough light. The natural light available can also be a source of lumens depending on how much natural light your home receives.
Wattage
Wattage is the amount of energy it takes for a bulb to produce light. Usually lights with higher wattage produce more light. Wattage isn’t a great measure for the amount of light produced by a bulb though because LED and fluorescent bulbs both use less energy to produce light than HID bulbs. Wattage does play a role in your electric bill, though, so it’s important to take wattage into consideration. It’s usually better to set up multiple less powerful fluorescent or LED bulbs rather than getting just one bulb with the highest wattage possible.
Full-Spectrum
Full-spectrum light is important for bonsai that are a fruiting or flowering species. Both LED lights and HID lights provide full-spectrum light. However, you can buy fluorescent lights that provide dual spectrum light, they just aren’t as common. Regular fluorescent lights provide blue light that is good for foliage but doesn’t cover what bonsai trees need for fruit or blooms.
Grow Light Positioning and Heat
The positioning for grow lights depends on the type of light you choose. You’ll likely need to do some trial and error when positioning lights near your bonsai. Here’s what you need to know about positioning each type of light and how much heat each type produces:
- Fluorescent lights should be placed between 2 to 10 inches from your bonsai foliage. Fluorescent lights need to be close in order to be effective. Some bonsai can handle the light being as close as 2 inches away, but others will begin to develop burnt leaf tips. Watch carefully for a few days after setting up the lights, and adjust as needed. Fluorescent bulbs do not put off too much heat, so they don’t dry out the soil too quickly.
- HID lights need to be placed at least 20 to 24 inches away from your bonsai foliage. Adjust as needed while monitoring closely. HID lights get very hot. Tropical bonsai trees may appreciate the extra heat if you are in a cold climate, so you may be able to move the light closer than 20 inches, but not all bonsai will want to be near that amount of heat.
- LED lights should be placed about 10 inches away from your bonsai foliage. Adjust as needed depending on how your bonsai responds. LED lights produce very little heat, so you don’t normally have to worry about them damaging your bonsai.
Grow Light Features
While you can buy basic grow lights, there are a few features that make it easier for you to effectively use grow lights for your bonsai. After all, the more convenient it is to use grow lights correctly, the more likely it is that your bonsai will stay healthy while indoors. If using grow lights takes too much extra work, you might find that you start neglecting your bonsai over the winter months.
Dimmable
Using grow lights with a dimmable option affords you better control over the amount of light your bonsai receives. Some bonsai prefer less light during the middle of winter, so dimmable lights allow you to come closer to mimicking what natural light does during the winter months.
Timer
In my opinion, a timer is one of the best features a grow light can have. Most bonsai trees need a certain number of dark hours, so you should not leave grow lights on 24 hours a day. A timer lets you consistently provide just the right number of hours, and makes it easier to ensure you don’t accidentally forget to turn the grow lights on or off each day.
Fan
If you are using HID lights, you’ll likely need a fan to prevent your bonsai from getting too hot while the lights are on. A fan isn’t as necessary if you are using fluorescent or LED lights.
Best Grow Lights for Bonsai Trees
- Best all-in-one LED grow light: Phlizon 1200W LED Plant Grow Light Full Spectrum
This light is perfect for people who don’t want to have to fuss too much with their grow lights. There’s a setting for foliage, one for flowering, and one for both. It’s easy to set up and works well consistently.
- Best adjustable LED grow light: Grow Light Abonnylv Floor LED Grow Light With Stand
This light comes with three bulb heads and a stand that make it easy to reposition the lights as needed. The LED light provides full-spectrum light, and it’s possible to adjust the brightness as needed. There’s also a timer included, which makes it easy to give your bonsai just the right amount of light it needs.
- Best budget option: GE Grow LED Light Bulb
This bulb is perfect for those who only need to supplement light for one bonsai or only need a little extra artificial light. The bulb will fit into a regular lamp and will look perfectly normal in a living room or other home space. It’s easy to use, easy on your budget, and easy on your eyes.
- Best grow light for large bonsai collections: SPIDER FARMER SF-2000 LED Grow Light
This full-spectrum grow light is energy-efficient and provides adequate light for a number of bonsai trees at once. The light comes with a dimmable knob to adjust the output. It’s quick and easy to set up, and the best choice for bonsai owners who need to provide light for several bonsai at once.
Verdict: Choosing a Grow Light for Bonsai Trees
Choosing the best bonsai grow light for you really depends on what you need for your situation and setup. In general, I’d recommend selecting an LED grow light because LED has more advantages and fewer disadvantages than the other types of light available.
When it comes to model and setup, there are lots of grow light options to choose from. Based on your setup, the best grow light for you may be different than the best grow light for someone else.
FAQ: Bonsai Grow Lights
FAQ: How do I know if my bonsai is getting enough light?
The first signs of bonsai suffering from lack of light tend to be growth slowing down followed by yellow leaves. If you notice these signs when you bring your bonsai indoors (and you’re certain the problem isn’t due to lack of water), your bonsai probably needs more light.
FAQ: Can a bonsai tree live in low light?
A few bonsai trees can live in low light conditions. If you don’t have a lot of natural light and can’t supplement with artificial light, try species like ficus, Hawaiian Umbrella, or Lucky Bamboo.
FAQ: Do bonsai need darkness?
Bonsai need a certain amount of darkness to thrive. When using grow lights with bonsai, do not leave the grow lights on for 24 hours a day.
Bonsai With Us!
The Bonsai Resource Center is here to help you learn about all things bonsai and provide you with the tools you need to keep your plant healthy and strong. Explore our other articles, visit our online shop, and connect with other bonsai lovers in our Facebook group to learn everything you need to know about this rewarding hobby!
