While it is true that you can keep bonsai trees indoor, this is only true for certain trees. Before placing your tree indoors, you should first figure out what tree you have. Tropical and subtropical trees are the only ones that can thrive indoors. These trees need high, stable temperatures all year round. This can be achieved outdoors only in certain climates.

Indoor vs Outdoor trees

As mentioned before, indoor bonsai trees need high, stable temperatures consistently all year. Outdoor bonsai trees, on the other hand, need to be exposed to the changing of the seasons. Outdoor trees experience dormancy periods in the winter and another small one in the summer, indoor trees do not. This dormancy period is completely natural in outdoor trees, but very unnatural and unnecessary for indoor species. If outdoor species do not receive this dormancy period, they will grow weak and can die. 

Caring for an Indoor Bonsai Tree

Taking care of bonsai trees is different from caring for a regular potted plant. Bonsai trees are planted in shallow containers in order to limit their nutrients and water intake. Indoor bonsai trees are also used to lots of light and high humidity, which can be hard to emulate in your household. 

Light

Light is one of the most important factors in caring for a bonsai. These trees need lots of light with as much light intensity as possible all year long. This can be hard to accomplish indoors, but it can be done. Placing your tree directly in front of a South facing window will ensure the tree will get as much natural light as possible. That being said, it is still very possible that your tree still isn’t getting enough light. Adding artificial lighting for around 10 hours a day will help significantly. 

Humidity and Temperature

Indoor bonsai also need high humidity all year round. Your tree needs higher humidity levels than the ones in your household, especially when using air conditioning and heating. Circulating air from outside by opening a window during the daytime will help. To increase humidity, you can try placing a humidity tray filled with water underneath the tree’s pot. Be careful not to let the tree’s roots soak in the water, though, as this will cause the roots to rot.

Tropical trees also need high temperatures all year, close to the temperatures in your living room. Subtropical trees, on the other hand, thrive in a low temperature winter. These trees like temperatures lower than your average living room.

Watering and Fertilizing 

Another very important part of caring for a bonsai is watering. How much water a bonsai tree needs varies from tree to tree, but there are some general guidelines you can follow for every tree. The first being that you should never water a bonsai tree on a routine or schedule. Check the soil’s moisture levels every day or a few times a day in the hotter months. You can check the soil using your finger, a chopstick, or a moisture meter. If the soil is dry, water generously until the water starts dripping out of the drainage holes at the bottom of the pot. Then repeat this process once more. Do not water your plant when the soil is already wet. This can cause root rot and will eventually kill the plant if left untreated.

All bonsai fertilizers contain the elements Nitrogen (N), Phosphorus (P), and Potassium (K). Each element serves its own purpose. For indoor bonsai trees, balanced fertilizer should be applied consistently all year round because they lack a growth period. The packaging should tell you how often to apply the fertilizer.

Caring for indoor bonsai trees isn’t as hard as one may think. So long as you care for your tree properly, your tree should grow healthy and strong. The tree should receive as much light as possible during the day. Constant high humidity is required all year round, and temperatures should stay relatively high for tropical trees, lower for subtropical. Water your tree when it needs to be water, never on a routine. Fertilize constantly all year round. In time, you will learn your tree and will be able to care for it much easier.