Updated: Jan 7
Todays topic is something i see asked a lot on social media pages, The question is usually something like " it has been raining for a few days straight, should i move my Bonsai out of the rain? " Lets take a look.
Todays article wont be super long or technical, but hopefully it will put some peoples minds at ease. So right now here in Australia we have having massive amounts of rain fall in the north east of Australia, We actually had the same event this time last year. But no matter where it happens in the world those who have not been in the hobby for very long have the fear that if it rains for too many days straight their trees will get over watered. In short this is not something you have to worry about, But its a good opportunity to learn something that will benefit you in the long run.
First lets have a quick chat about over watering and what the problem usually is. When we talk about over watering the problem is usually not the amount of water entering the pot but how much stays in there. With an in organic substrate it is almost impossible to overwater a tree, Now i say almost impossible because Akadama breaks down and some people ( me included ) use 100% Akadama for some trees. now while this is still somewhat experimental using 100% Akadama one thing you do have to keep in mind is that unlike pumice or scoria the Akadama will break down and begin to hold more and more water in the pot as it does so. With most other in organic mix's though we have other mediums such as pumice and scoria that help keep the mix aerated even as the Akadma breaks down, This also helps dump any substantial water levels left in the pot after watering. This is also where our drainage layer plays a crucial roll.
Now I've said it time and time again but a full organic mix ( garden soil ) in a Bonsai Pot is a bad idea. You can check out some of my other articles for an in depth explanation but basically those trees with that mix will hold too much water low down in the pot while you keep watering the top of the pot each day thinking that the mix is dry because the surface looks dry.
So what exactly is the lesson here? Use in organic mediums in a Bonsai Pot and you wont have any issues with massive amounts of rain for long periods of time, As it rains the water will run straight through the pot pulling oxygen through with it. All excess water will drain straight out the bottom leaving you with a balance of water and oxygen still.
If you are using regular garden soil the pot is just filling up with water, kind of like a pool. It will only drain properly once the rain stops. There is very little oxygen available to the root system and over a long period this can indeed be catastrophic for your tree. BUT this needs to be a long period of time. A week of rain wont hurt the tree too much, But i can tell you it would much rather be in that in organic mix that is still constantly breathing fresh oxygen even in the middle of a massive down pour. If you live in a part of the world where rain for weeks on end is a common occurrence then in organic substrates will be your best friend for happy and healthy trees.
Like everything in Bonsai it is dependant on a persons particular situation, My advice is try and use the best practise of putting in organic mediums in your bonsai pot. Drainage isn't the only advantage you will gain by doing that. Once again i have other articles on this. If you are using garden soil in your bonsai pot and it has been raining for over a week i would begin to start moving those trees as root rot can set in from around 10 days of the root ball being constantly full of water and low on oxygen.
I know this article is shorter then i usually write but it is a fairly simple topic. I hope it has helped you understand what to do in a situation where the rain just wont let up!
Until Next Time, Enjoy Your Bonsai Journey.