The most crucial aspect of caring for a bonsai tree is watering. The frequency of watering depends on several factors such as the tree species, size of the tree, pot size, time of year, soil composition, and climate. Consequently, it is impossible to determine an exact watering schedule for your bonsai. However, understanding some basic guidelines will assist you in observing and knowing when your tree requires watering.
How often should I water my Bonsai?
As mentioned, the frequency of watering a Bonsai tree depends on numerous factors, making it impossible to provide an exact guideline. Instead, you need to observe each tree individually. The following general guidelines will help you water your Bonsai tree appropriately:
Water the tree when the soil is slightly dryThis means you should not water when the soil is still moist but only when you notice it has become slightly dry. You can use your finger to check the moisture level of the soil at a depth of about 1 cm. However, be cautious not to let the tree become dehydrated. With more experience, you will be able to visually determine when a tree needs watering, rather than relying on intuition.
Avoid watering on a fixed scheduleInstead of watering on a regular daily basis, continuously monitor each tree until you know exactly what you are doing.
Use an appropriate soil mixThe soil mix greatly influences how often a tree needs to be watered. For most Bonsai trees, a mix of fired clay soil (akadama), pumice, and lava rock in a ratio of ½ - ¼ - ¼ is suitable. However, use a mix that retains more water (by increasing the proportion of akadama or even adding peat moss) if you cannot water the tree frequently. Read an article about Bonsai soil mixes for more information.
When watering these plants, you will notice that a significant amount of water tends to flow directly out of the pot, and the roots become tightly compressed to the point where the soil cannot easily absorb water. These plants need to be repotted!
When to Water Your Bonsai Tree
It is not critical to water your Bonsai at a specific time. However, there is a recommendation to avoid watering (especially with cold water) in the afternoon. By that time, the soil has been heated by sunlight and will cool down rapidly if cold water is applied. While you may consider this advice, it's important to understand that if the soil has started to dry out, you should water the tree regardless of the time!
How to Water Your Bonsai Tree
As explained, water the tree when the soil starts to slightly dry out. However, when the tree needs water, it should be thoroughly watered so that the entire root system gets moist. To achieve this, water until you see water starting to flow out from the drainage holes, and you can repeat the process a few minutes later.
Water the tree from the top using a watering can with a good nozzle; it will help prevent the soil from being washed away. Rainwater is preferable (as it contains no impurities), but if it is not available, regular tap water is also fine. There are automated watering systems available, but they are often quite expensive.
When watering, be careful and ensure that the entire root system of the tree gets wet!