How to Care for a Bonsai

Although they are small, bonsai trees need the same sun, air, and humidity as their larger relatives. A terrace, balcony, garden, or windowsill can all be suitable places for them. If you want to keep one indoors, it is important to consider whether the space offers the right conditions for the tree to adapt. That will depend mainly on light and humidity: for example, the bonsai can be placed near a well-lit window, in a cool room, and away from heating devices, fireplaces, or appliances that give off heat.

The ideal setup is one that places the tree at a comfortable height for viewing, never directly on the floor. A good option is to place it on wooden shelves, which do not reflect heat, or on stacked pallets.

It is impossible to say exactly how often a bonsai should be watered, because the answer depends on several factors: the tree species, its size, the shape of the tray, the season, and the climate where it is kept. Even so, there are a few basic rules that will help your miniature tree stay healthy and avoid stress.

Routine watering at the same time every day should be avoided. It is always better to observe each tree individually and check the moisture level in the soil, for example with your fingers, to make sure the substrate remains consistently damp. It is also best not to water at midday. At that time, both the pot and the soil are very hot, so fresh water can cool the bonsai too quickly and affect its health.

Another useful trick, especially if the bonsai is kept in a living room or other indoor space, is to mist the leaves from time to time to clean them and refresh the tree. Bonsai kept indoors do not receive rainwater, so dust naturally collects on the leaves.

Potassium is essential for the proper development of a bonsai. For that reason, you should look for fertilisers with a high potassium content, one of the tree’s preferred nutrients, along with phosphorus, calcium, magnesium, and sulphur. On the market, you can find both liquid and solid fertilisers. If you use a liquid product, it can be dissolved in irrigation water or applied as a spray over the leaves; if you choose a solid fertiliser, it should be distributed evenly over the soil surface. When is the best time to fertilise? The most suitable moments are during the tree’s growth phase, in spring or at the end of summer.