This is how
This is how I do it.
I water all of my trees once a day. I have a bench that gets morning sun and afternoon shade and one bench that gets full sun all day long. When I water my bonsai I make sure that I soak the soil of the bonsai so water is running out of the bottom of the pot. Not just a little water. I soak my soil with lots of water. If you are using the right kind of soil, there is no way to over water your bonsai this way. I then make a second pass over the same trees on that one bench making sure to soak my trees soil, again with water running out of the bottom. I then move to the second bench and do the same thing.
Why make two passes?
I make two passes for a few different reasons. One reason is to flush the soil of dust and to draw fresh air into the root zone. A second reason would be too cool the roots and pot. Another reason is to soften my organic fertilizer cakes or to reactivate my inorganic fertilizer salts. Finally, a different reason would be to make sure I am getting the whole root zone wet. When I make my first pass with my hose I think of it as “priming my soil”. I am “pre-wetting” the soil. For me, the second pass is really when the watering and fertilization happens because my soil is ready to receive the water and my fertilizer is softened and ready to break up.
When using inorganic fertilizers, the first pass wets the soil and the salts of the fertilizer, reactivating the fertilizer and “priming” the soil. If I was applying liquid inorganic fertilizer I would do this during the second pass because the soil is ready. I imagine it like adding a drop of food coloring to a paper towel. The first pass primes the soil getting it wet, while the second pass allows the soil to receive the fertilizer and distribute it better, like adding food coloring to a wet paper towel.
Take a dry paper towel and drop one drop of food coloring on to it. Then follow that up by doing the same thing on a wet paper towel. The food coloring should disperse more on the wet paper towel.
That same effect is why we “prime” the soil with the first watering.
My prefered method of fertilization
My preferred method is using organic fertilizers. I obviously recommend Sumo Cakes. When we use organic fertilizers and we make the first pass with our water hose, we are “priming” the soil. With this first pass, we are also loosening up the particles of fertilizer that already reside in the soil along with softening the organic fertilizer cakes that sit on top of the soil. If you use tea bags for your fertilizer you are also getting the tea bags ready. I like to think of this first pass as taking a hot cup of water and placing a tea bag into the water. Nothing much really happens.
On the second watering, again is when I feel everything happens. The fertilizer cakes on top of the soil visibly start to break up as pieces fall off of the cake and get washed into the soil. The tea bags have had a chance to steep. The second pass of water over the tea bags in my mind is as if you were to move the tea bag around in your cup of hot water. The tea releases the nutrients into the soil.
Other Reading On This Site
Why I like Organic over Inorganic Fertilizers
The reason I like to use organic fertilizer cakes vs. inorganics is that of the constant feeding the bonsai get with every watering. Liquid inorganics, who knows how much your bonsai is getting fertilized if it rains all day. Is all of the fertilizer washed out of the soil? Who knows. At least with the cakes, you can see how much of the cake is still there.
Organic fertilizers also help promote the growth of Mycorrhizae. Again, you can read more about that in this article (Mycorrhizae, the Beneficial Symbiotic Relationship). Organic fertilizer promotes a healthy root zone while inorganics in my mind, focus solely on top growth.
Most fertilizer products do not provide all of the nutrients that our bonsai need. You will end up buying multiple products to provide your bonsai with all of the nutrients they require. I am proud to say that Sumo Cakes makes feeding your bonsai easy, as these cakes have a guaranteed analysis of providing 9 micronutrients along with all 3 secondary nutrients and the normal NPK. Also included in Sumo Cakes is a plethora of Mycorrhizae species to help promote a healthy root zone.
Remember to make two passes with your water hose. Your trees will love you more for it.