As mentioned previously, how often a Bonsai tree needs to be watered depends on too many factors to provide an exact guideline. Instead, you need to observe your trees individually. The following general guidelines will help you to get Bonsai watering right:
- Water your trees when the soil gets slightly dry
This means you should not water your tree when the soil is still wet but only when it feels slightly dry; use your fingers to check the soil at around 0.4’’ (one centimeter) deep. But never let a tree dry out completely! Once you get more experienced you will be able to see (instead of feel) when a tree needs watering.
- Never water on a routine
Keep observing your trees individually, instead of watering them on a daily routine, until you know exactly what you are doing.
- Use the right soil-mixture
The soil-mixture greatly influences how often trees need to be watered, for most Bonsai trees a mixture of akadama, pumice and lava rock mixed together in a ratio of ½ to ¼ to ¼ should be fine. However, use a mixture that retains more water (by using more akadama, or even potting compost) when you cannot water your trees that regularly.