Watering is a crucial aspect of taking care of bonsai. However, determining the appropriate watering schedule can be influenced by a multitude of factors: the species of the tree, its size and health, the time of year, the soil mixture and condition, as well as, of course, the location of the bonsai with its specific sun and wind exposure.

In this beginner’s guide, we will explore some myths surrounding bonsai watering and provide you with the facts you need to ensure that your trees thrive.

Myth 1: Bonsai should be watered every day

It is important to note that watering a tree too often can be detrimental to the health of a bonsai, as it can lead to root rot and ultimately kill the plant. It is best to wait until the soil feels dry to the touch before watering your bonsai again. The frequency of watering is key in ensuring the health and vitality of the tree. In some instances this may very well be everyday, but in others it is certainly not.

Contrary to popular belief, you cannot overwater a tree while watering it. The risk of overwatering comes from watering too often, rather than too much at one time. It's important to strike a balance between providing both enough water and air for the tree's needs, without waterlogging the soil and without causing water to stay pooled around the roots constantly.

Myth 2: Bonsai should be watered from the top

This really comes down to the soil compactness and size of the tree. While it is true that watering from the top is the most common practice, it happens that the water runs off and does not properly reach the roots if the soil is too compacted. Therefore with Shohin or Mame bonsai, dipping the pot in a bucket of water can be done for trees that require it.
For these smaller trees the amount of soil is very small and can be washed out with too strong of a hose, in these cases you could try watering the bonsai from the bottom by placing the pot in a saucer of water and allowing the soil to soak up the water.

Myth 3: Bonsai should be watered in the morning

When your tree is thirsty, water it. There is no specific time to do so, really. Some species will allow you some slack but be careful with unforgiving species such as maple and buna which are easy to dry quickly. Watering bonsai during the day is convenient as you can check the soil more easily but you should always remain careful about a hot and sunny day.

Myth 4: Bonsai should be watered with cold water.

Cold water can shock the roots and stress the plant, especially when the soil is warm from being in the sun. This is because the sudden temperature change can cool the tree too quickly. In such cases, it's best to use room temperature or slightly warmed water when watering trees that have been exposed to the sun for an extended period.

By understanding the truth about bonsai watering, you can help keep your tree healthy and beautiful for years to come. However, it's important to note that watering bonsai is a nuanced art with many subtleties and potential topics to explore beyond the four myths we covered in this article. Stay tuned for future articles where we'll dive deeper into the refined techniques of bonsai watering.