Despite the common misconception that bonsai trees are dwarf species, these man-shaped trees growing in pots are just ordinary trees that have been pruned and forced to grow like a miniature tree.

The key point here are the trees. Neither plants, nor flowers, nor plastic sculptures. Trees. And trees don’t grow inside houses or in underground caves, regardless of what Jules Verne told us about underground trees in Journey to the Center of the Earth.

Now, what is missing from an interior regarding the forests? Fresh air, perhaps. Swarms of bees, I hope so. But it sure lacks direct sunlight throughout the day.

Even with an open space loft, the amount of sunlight coming through the windows is limited by the exposure the bonsai tree has. With a northern exposure giving the least amount of sunlight.

The simplest solution is to mimic the behavior of the sun and rotate the tree. By rotating it at regular intervals, direct light from the window will shine on your bonsai’s foliage, allowing it to develop healthy branches all around.

This of course means that you need to consider another aspect of bonsai care, in addition to the already rigorous activities like watering and pruning.

An alternative solution is to try so-called daylight lamps. These types of lamps are quite expensive, since they are used in phototherapy, literally the treatment of a disease caused by exposure to sunlight. Phototherapy lamps include the full spectrum of daylight, including some ultraviolet radiation, and are popular in the alternative health niche. The use of such a light does not have the adverse effects that ordinary incandescent bulbs have, that is, they radiate only a narrow spectrum of yellow-red light.

However, you need to check two important factors when choosing such a light. First, that it is in fact a phototherapy bulb similar to sunlight. The so-called “daylight” fluorescent lamps found in department stores are often 6400 Kelvin and only approximate the color temperature of daylight.

Also, the CRI, or Color Rendering Index, needs to be around nine to be effective. The CRI measures the precision with which the lamp emits light and is mainly used in photo studios or printing agencies where proper color reproduction is mandatory. But it is also essential for the health of your bonsai.

Now, if you go the artificial light route, this doesn’t mean you shouldn’t rotate the tree at all. Otherwise, there will always be a marked difference between the side that receives direct sunlight and the one that is artificially lit. But you can reduce the rotation load and take a more relaxed approach, making sure that, on average, all sides of the tree receive the same amount of sunlight and artificial light.

One last piece of advice: sunlight does not diminish with distance. Or rather, it does so slightly that on a terrestrial scale this decrease is considered negligible. On the other hand, artificial light decreases with the square of the distance.

Sound complex? It is not: all this means is that if you place your bonsai 1-2 meters from the window, the amount of sunlight will be more or less the same. On the other hand, if it is placed two meters from the artificial lamp, it will obtain a quarter of the light that it would obtain from a distance of one meter.

So make sure you have it much closer to the lamps than the window to even out the amount of light exposure.