A common misconception about Bonsai trees is that they should be kept indoors. In fact, most Bonsai trees should be placed outside, where they are exposed to the four seasons just like normal trees are. Only tropical and subtropical plants can survive in the indoor climate of your house; where temperatures are high and stable throughout the year.
Alright, so I need a tropical Bonsai tree. Which one?
There are several trees that you can grow indoor, but by far the most common (and the easiest to care for) is the Ficus Bonsai. The Ficus is tolerant to low humidity and can withstand quite a lot; a good choice for beginners.
Indoor Bonsai trees; a Ficus, Carmona and a Chinese elm.
Why can’t I keep temperate (non tropical) Bonsai trees indoor?
The most important reason, as stated above, is that temperate trees need a period of dormancy (in winter). In this period the yearly growth cycle ends, and the tree prepares for the next cycle which will start again in early spring. A tree becomes dormant when temperatures and light intensity gradually decrease over the course of several weeks, which wouldn’t happen when you keep your trees indoors.
Indoor Bonsai tree care movie
Indoor Bonsai tree care
Caring for an indoor Bonsai tree is different from that of normal potted house plants. The main reason is that Bonsai trees are planted in small pots and therefore have limited storage for nutrients and water. More important is that tropical trees are used to much light and high humidity; circumstances that are quite difficult to create indoors.
Specific care of indoor Bonsai species:
The main problem with keeping a tropical indoor Bonsai tree is that the intensity of light indoors is much lower than outside. Trees won’t die immediately when light intensity is too low, but growth will decrease, eventually weakening the plant. Therefore, make sure to place your Bonsai at a bright spot, preferably directly in front of a window facing the south.
Even when you have a window facing the south, chances are that the intensity of light is still too low. Artificial lighting can help, for example by using fluorescent lighting (with radiating growth-friendly spectra) or light-emitting diode lighting about 10 hours a day.
Another issue with keeping a tropical Bonsai tree indoors is that the tree needs a relatively high humidity, much higher than the indoor conditions of your house (especially when you use heating or air conditioning). You can increase humidity near your Bonsai tree by placing it on a humidity tray filled with water and by misting your tree a few times a day. What also helps is to circulate air from outside, by opening a window during the day.
3. Watering and fertilizing
The most important rule is; never water on a routine. Ignore the label attached to your Bonsai tree which states you need to water every 'x'days. Instead, monitor your tree and only water when needed. Please read the watering and fertilizing pages for more detailed information.
Tropical tree species need relatively high temperatures throughout the year, similar to the standard room temperature of your living room.
Subtropical Bonsai trees can withstand somewhat lower temperatures, and generally thrive when they enjoy a winter season with temperatures well below that of the standard room temperature.
To summarize, make sure to select the right tree species and take into account the specific care guidelines for indoor trees, and you will do just fine!