Updated: Jan 7
We have all seen the age old argument of Misting is good vs Misting is bad for your Bonsai, But who is correct? Lets take a look.
Surprisingly the advice to mist your Bonsai often comes from retailers who have no business selling Bonsai and giving care advise for them, They often give people bad advice like keep your bonsai indoors by a bright window, or dunk your tree once a week to water it. I have even heard of retailers telling people to give their tree 1 teaspoon of water a week indoors..... WHAT?
Now before we get into this i just want to say that both sides of the argument are correct, Yes misting can be bad for Bonsai but it can also be beneficial for Bonsai, like everything else in Bonsai it all comes down to understanding why you are doing it and what the goal is.
Lets start by saying that if your goal is to water the tree like this then you are way off. If a retail store told you to water your tree by misting the foliage i would suggest never buying any type of plant from them again as they clearly do not understand the product they are selling.
Ok now that we have that out of the way lets ask ourselves why do we mist?........ Challenge yourself here, before you read on can you think of why you might mist a Bonsai Tree and why you might not?
Now the goal of misting only ever has 2 goals, 1 is to cool the external extremities of the tree and 2 is to create humidity, but both achieve the same goal. When we mist either trying to cool the tree or create humidity what we are actually doing is trying to slow rapid transpiration in a tree. Think of transpiration like a human sweating, the hotter it is the more we sweat, this is just our bodies way of trying to cool us down to prevent us from cooking. Trees have a similar process in which they release moisture from their foliage and the tree re hydrates the leaf by moving water from the root system up through the tree and back into the foliage. During this process the tree is moving cool fresh water through its system keeping it cool, but you can imagine on a hot day if the tree is doing this a lot it is going to drain the amount of moisture present in the pot quickly which will require you to water more often, if you are not around to re hydrate your root system then the tree will suffer due to not being able to complete this process. Trees in nature have a big tap root that is deep down in the soil surface and tapped into an almost unlimited supply of moisture which is why you generally dont see large trees in nature suffer unless it becomes too tall and struggles to get resources to the very top of the tree. In a Bonsai pot the tree is not connected to any natural resources so it relies on us for its care. So as you can see the only real reason to mist a bonsai is too slow down the transpiration process on really hot days.
Now there is 1 other culprit for rapid transpiration and that is wind, On a day when it is windy constantly you will notice that your tree will dry out very quick, this is because as the wind moves over the surface of the foliage it draws the moisture out and the tree has to continually work to replenish that moisture. On windy days when im watering this is one of the only times i will actually wet the foliage as well as watering the soil surface as this just helps to slow down the transpiration by drenching the foliage.
Now lets talk about the downside to misting foliage or even watering your foliage.
This is pretty simple and wont need much explanation but the reason why misting your foliage or drenching it can be bad is if you are doing it without reason in cooler weather, think of winter for example, if you were to mist a juniper or drench its foliage that moisture isn't going to evaporate anytime soon, it will just sit and sit and sit in that foliage which is a welcome mat for fungal infections and rotting wood on your tree. This is also the reason why we do a late summer / Autumn prune on our trees to open up those interior sections of the tree to allow air and light to move though during the colder months.
Now before i leave you today i want to just point out 1 other thing that might confuse you in terms of what the foliage can actually take in. You will hear people talk about foliar feeding a tree which is something that can be done, it needs to be done early in the morning while the Stamata on the leaf is still wide open, as the weather warms up the Stamata will close to slow transpiration. Now on a sick tree we can spray a foliar feed or health tonic directly on the foliage to help it regain some health, almost like a drip for a patient in a hospital, this gives a dose of nutrients straight to the foliage, a trees foliage can take on nutrients up to 8 times quicker then the root system, but this is only beneficial in a health situation which is why we still feed through the root mass. The tree can not take on water in anyway that is helpful to the tree this way though, the water needs to move from the root system up.
I hope this article has helped dispel some of the myths surrounding misting and next time you see an argument with 2 people over misting you'll know that they are both correct and why.
Until Next Time, Enjoy Your Bonsai Journey.