…since we’ve been on the subject of watering earlier this month, why not keep at it?
This one is rather simple to relate. Sometimes, when watering our bonsai gardens, we might notice a tree that is always dry. It seems like minutes after we water it, the darn thing needs water again.
This should set off jangling alarm bells in our heads! Loud, nasty, persistent ones.
When a bonsai dries out this fast, there is often a very simple reason. The interior of the soil mass is not getting saturated. Very old established bonsai sometimes have this problem. It can happen with nearly any soil type, but is very common with Turface, Oil-Dri, and any soil containing peat moss. All of these have rehydration problems when dry.
A combination of issues can cause the interior area to become bone dry:
- soil choice
- erratic watering schedule
- compacted interior soil
- ‘veneer watering’ (watering with only a light pass that does not completely saturate)
Of the issues, an erratic watering schedule and veneer watering are the worst. Inconsistent watering can cause some pots to get too dry, and then light watering simply runs down the sides of the pots and into the bottom after encountering very dry interior soil.
Once the interior becomes bone dry it can be hard to rehydrate. The best way to restart hydration is to soak it from the bottom up. In my yard, I might see a couple trees a year that need a soak. After the soak, usually with more attention to watering afterwards, the problem is fixed.
- The reason this is such a serious issue is that eventually all the interior roots will die, leaving only those next to the sides of the pot and the bottom—which are really the worst places for a bonsai to grow roots.
To rephrase and sum up, when you see a tree that seems always to be dry, consider rehydration with a bottom soak. Usually this only happens with very established, old bonsai that have a mature root system. Most trees that have hydration problems need an extra pass or three with the water hose to keep from revisiting the ‘dry death zone’, which would be a pretty good title for a bonsai horror movie, come to think of it. Likely somewhat limited audience.