Bonsai Winter Care: Caring For Bonsai In Winter As Needed

Bringing them indoors and a slight change in the care routine can do wonders for your bonsai’s health

Bonsai Tree In Winter

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In most parts of the world, trees are subjected to harsh conditions and temperatures as low as -10 degree Celsius during the winters. But fortunately, their roots are rooted deep into the ground. Hence, they do not experience any trouble bearing the brunt of the cold weather.


However, with bonsais, the situation is not the same. People plant their bonsais in smaller containers. Consequently, it is hard for the roots to guard themselves in the winter.


But, bonsai trees in winter begin preparing for the freezing weather just like any of their full-sized counterparts. Since bonsai is not rooted in the ground, it is particularly susceptible to extremes of the winter. Hence, undertake some protective measures to guard the plant because the bonsai’s health depends on how you shield it against harsh weather.


Winter is the best period for rest for the bonsai. So, in this guide, we will study in detail the care for bonsais in winter. Let us dive right in.


What Is The Temperature Tolerance for Bonsai?

Temperature Tolerance for Bonsai

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Temperature is one of the most pivotal bonsai winter care aspects. Across the winter, the indoor bonsais must be kept warm but not hot. Their ideal required temperature ranges between 55 and 75 degrees Fahrenheit.


But, sadly, this range might not be preferred by all kinds of bonsais. Thus, the plant demands a temperature range depending on its origin. Caring for indoor bonsais would mean maintaining a standard room temperature.


If you have a tropical bonsai, you can plant it in a location where you can maintain the room temperature around the year. However, bonsais cannot survive the frigid weather. Hence, they must not be placed in cold places or near an open window during the winter.


As a small bonsai grower, instead of offering specialized protection to bonsai trees in winter, you need to place the plants in a spot where they can be kept warm around the year. We recommend this because, in their natural habitat, the plant grows sans a dormancy period. They seek temperatures between 55 and 65 degrees during the night and 65 and 75 degrees Fahrenheit during the day.


It implies that you do not have to take exquisite measures for indoor bonsai because, in most homes, the stated range is typical. But growers must be careful and prevent cold bonsai roots and feet. It mainly happens when the roots are colder in the indoor space. To avoid this, we recommend growing the bonsais near a heat source. It ensures that the plant does not lose moisture and maintains humidity.


Fortunately, sub-tropical and Mediterranean indoor bonsai winter care includes growing in cooler temperatures. It is the non-tropical bonsais that need specialized care. They seek a cool environment in the window. So, you can place them on a cool window ledge or a cold room.


Sub-tropical bonsai are low-maintenance. So, not much goes into their outdoor bonsai tree winter care. You can place them outdoors sans any fear but to guard them against drafts.


Can Bonsai Trees Survive Winter?

If you have a deciduous bonsai tree, it may lose all its leaves during the winter and enter dormancy. However, some deciduous trees do not necessarily lose their leaves annually. For instance, boxwoods maintain their leaves for over a year. If you have an evergreen bonsai, it will not lose its foliage.


However, during winter dormancy, the bonsai might change its foliage color. But, if you have a tropical bonsai, read above for the temperature ranges that bonsai can manage.


While cool temperatures can stress some tropical plants and prolonged exposure might even kill them, others can withstand cold effortlessly. Read below as we discuss the necessary measures for caring for bonsai in winter.


Prep Your Bonsai Before Winter

Prep Your Bonsai Before Winter



Some bonsai species are hardier than others. The plant’s hardiness depends on its native geography. As stated above, temperate trees demand cold weather in the fall to enter dormancy. For other species, you must wait until the first frost before you put them in storage or take other suitable measures for protecting bonsai in winter.


A. Mindful pruning

Another aspect necessary for winter preparation is pruning the parts of the bonsais at least two months before winter because if you trim any later, the bonsai will not have ample time to recover. It can make them weak.


B. Fertilizing for bonsai tree winter care

Trees yield carbohydrates and sugars to prevent themselves from freezing. It is pivotal to ensure that you feed them well to prevent freezing. Hence, during the warmer months, you need to get the bonsai ready to withstand the impending harsh weather. So, feed them fertilizer strictly during the growing season and not during late fall or winter.


Fertilizing between late spring and early fall works best. You can find several types of fertilizers, but a balanced 10-10-10 fertilizer once a month in the warm season can help with outdoor bonsai tree winter care.


C. Bring them indoors

Bring them indoors


In colder areas, the temperate deciduous trees prepare for the upcoming winter by dropping leaves to curtail moisture loss and hardening the new growth during autumn. This dormancy period is pivotal for Bonsais too.


However, many believe in indoor bonsai winter care and move the plant indoors. Over-nurturing and overprotecting your plant can do more harm than good. Of course, subtropical trees are an exception to these as they must be placed indoors during the winter if the temperature goes below 15 degrees Celsius.


Regardless of the variety, every bonsai grower should know the drill and measures for protecting bonsai in winter.


D. Store Them in a Cold Frame

There are several methods of storing the bonsais during the winter. Some bonsai enthusiasts place the tree in a temperature-controlled environment, cold frame, or a greenhouse, ensuring the temperature is around 34 degrees.


However, others keep it in an unheated garage attached to the house for bonsai tree winter care. It is one recommended measure for places where the temperature repeatedly goes below 15 degrees Fahrenheit. This cold frame helps lower the fluctuations in the temperature and guards your tree against significant temperature drops at night. It also ensures that the tree does not dry out with the force of strong winds.


E. Insulate the roots

If such a shelter is unavailable, you can place the trees on the ground and raise them with a thick mulch layer to shield the roots. Alternatively, you can plant the whole container in the soil and lift it back in the spring.


For the necessary bonsai winter care, you should try to keep the roots at a stable temperature, avoiding the swings between thawing and freezing. It also helps to place a Styrofoam cover around the pots.


F. Keep a check on the watering schedule

Some people believe that bonsais do not need water during the winter. It is one wrong notion because the plant still seeks a small amount of water during the winter.


Placing snow on the trees and storing it in an unheated garage is an excellent method of caring for bonsai in winter and meeting its watering needs because as the snow melts, the plant receives water. Alternatively, you can also lightly water the plant if the soil seems dry to the touch.


G. Cover the bonsai

Cover the bonsai

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If the temperature during the night is mild, approximately 25 degrees Fahrenheit, you do not need a cold frame. But, protecting them against robust winds helps. The best solution is placing the tree on the ground to avoid significant temperature drops.


Alternatively, covering bonsai pots with insulation or a bedsheet may also help. Some also recommend covering it with plastic and veiling it with a newspaper or cloth around the exterior. Plastic exposure promotes heat and conducts temperature. So, when the sun rises, remove the plastic and the cloth instantly to prevent the leaves from getting burnt.


H. Keep it protected from the wind

Some people like to overwinter the bonsais outdoors instead of moving them to some shelter or garage. In this case, it is imperative to place the plant where it gets necessary protection from the strong winds. Fencing can be a good bonsai winter protection. The East side of the wall also works as a windbreak from the Westerly cold winds.


I. Use the grow lights to maintain the temperature

In winter, the natural light from the sun is inadequate. Thus, you may need artificial lights to help with your bonsai. You can keep the bonsais near the window. It aids it in receiving sunlight and not getting exposed to excessive UV rays from the grow lights.


What Happens To Bonsais During The Freeze?

Bonsais can be hardy and can cope with cold weather. In most situations, it is not the cold that necessarily harms the tree, but dehydration inflicts more severe damage. If the soil enveloping the bonsai roots freeze, the roots stop functioning. Thus, they no longer draw in the water.


However, the top of the tree continues to release water. Hence, it is the prolonged freezing spells that can cause damage to the plant. It worsens when the freezing weather pops with the harsh winter sun or the strong wind that further dries the tree. Hence, you can eliminate massive harm from the tree through bonsai winter care placement. You must put them in a more sheltered position away from the harsh sun or wind exposure.


Can Bonsai Trees Survive Indoors In Winter?

Bonsai Trees Survive Indoors In Winter

By Photography by Alexandra Rudge/gettyimages

As already discussed, several subtropical and tropical trees can grow indoors. The easiest and the most common bonsai to care for is the Ficus Bonsai. It is resilient and can tolerate low humidity. Hence, it is a good pick for beginners.


Other varieties like the Fukien Tree, Dwarf Jade, Sweet Plum, and Hawaiian Umbrella grow well indoors in the winter. So, if you pick any of these trees and offer them good care, your tree will thrive.


But you cannot keep temperate trees indoors. They demand a dormancy period as a part of their bonsai winter care because their annual growth cycle ceases, and the plant conditions for the next cycle begin in the early spring.


Over the next few weeks, when the light intensity and temperature drop, the plant becomes dormant, which is not the case if you keep your temperate bonsais indoors. Subtropical and tropical bonsais do not need this dormancy period.


Indoor Bonsai Tree Care – How Is It Different?

Indoor Bonsai Tree Care

By Cristian Negroni/gettyimages


Bonsai trees in winter need different care from the standard potted plants. It is because bonsais are planted in smaller pots and have curtailed storage for water and nutrients. Moreover, tropical trees cherish high humidity, and often some prerequisites are tricky to mimic indoors. Now, let us discuss the care guidelines for indoor bonsais.


A. Sun

Naturally, the intensity of light indoors is lesser than outdoors. But trees do not die if they do not get ample light immediately, but they have stunted growth. It also weakens the plant over time. Hence, we recommend placing the bonsais in a spot that receives bright sunlight, particularly in front of a south-facing window.


In some homes, even the south-facing window might not allow ample light for the plant. So, you can make up for this deficit with artificial lighting. It is also a beneficial tip for bonsai trees in winter because the sun is not as bright in the colder temperatures.


B. Humidity

Most bonsai plants seek high humidity, but inside the house, the humidity is not as high, especially if you place the plant near an AC or a heating instrument. But you can amplify the humidity indoors by placing a humidity tray full of water underneath the bonsai. Alternatively, regularly misting the plant can also help. You can also boost air circulation by opening the window during the day.


C. Water

Never have a fixed watering schedule. For bonsai winter protection water it only when the topsoil feels dry.


D. Temperature

Tropical plants demand a high temperature across the year, but the standard room temperature can serve the purpose. But subtropical bonsais can bear lower temperatures too. So, they can thrive in winter even when the temperature is below the standard room temperature.


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Summing up
Please note that properly caring for bonsai in winter is beneficial for bonsai plants to survive and thrive. Bonsai are versatile, and you can grow them indoors and outdoors, provided you offer them the needed conditions and take active measures to shield them against harsh climates.