"Water once for the pot, once for the soil and once for the tree"

[Daniel_UK]

"Water three times: one for the pot, one for the soil one for the tree"

I decided to test this Japanese saying.

I have a fukien tea tree potted in 50% akadama and 50% kyodama (UK based hard absorbent fired clay product which can replace grit or gravel).
I measured the total weight of the bonsai in its pot, then watered it, until water poured quickly out of the drainage hole. I measured the weight again. I then waited 5 minutes and repeated.

Day 1:

Initial Weight (1129 grams)
After Water 1: 1190 (+61 grams)
After Water 2: 1197 (+68 grams)
After Water 3: 1201 (+72 grams)

It seemed that the saying was true. There was also a vague pattern emerging that the weight gain halved each watering. I would therefore expect: water 4 (+74) and water 5 to be (+75). I tested this further:

After Water 4: 1194 (+65 grams)
After Water 5: 1195 (+66 grams)

This felt a bit mysterious- "water three times" seems to be correct and watering more will not help. Surely, it should keep the same weight if the water filled porosity is full or gain weight if there is still some pores left to be filled; on the contrary, it went down.

I decided to try it again the next day:

Day 2:

Initial Weight (1129 grams)
After Water 1: 1195 (+66 grams)
After Water 2: 1198 (+69 grams)
After Water 3: 1205 (+76 grams)
After Water 4: 1201 (+72 grams)
After Water 5: 1203 (+74 grams)

The results were similar. I decided to try it one more day:

Day 3:

Initial Weight (1117 grams)
After Water 1: 1194 (+77 grams)
After Water 2: 1199 (+82 grams)
After Water 3: 1198 (+81 grams)
After Water 4: 1202 (+85 grams)
After Water 5: 1202 (+85 grams)

The pattern was broken. I did let it go drier this time before I started the test, hence the initial weight being lower.

Due to the different initial weights, I turned the results into percentages. I made the initial weight 0% of the water filled porosity and the highest weight for the day 100% water filled porosity. Of course, the pot already had some water in to begin with and I don't know the dry weight of the pot and tree so this is not accurate but allows me to make comparisons between the days:

Day 1:
Initial Weight: 0%
After Water 1: 85%
After Water 2: 95%
After Water 3: 100%
After Water 4: 90%
After Water 5: 92%

Day 2:
Initial Weight: 0%
After Water 1: 87%
After Water 2: 91%
After Water 3: 100%
After Water 4: 95%
After Water 5: 98%

Day 3:
Initial Weight: 0%
After Water 1: 91%
After Water 2: 97%
After Water 3: 96%
After Water 4: 100%
After Water 5: 100%

I then averaged these:

Initial Weight: 0%
After Water 1: 88%
After Water 2: 94%
After Water 3: 99%
After Water 4: 95%
After Water 5: 97%

This was based on one substrate mix in one pot so I cannot generalise the results, but the conclusions that I will take away are:

1. Watering 2 or 3 times will give you greater water retention than the first water.
2. The difference between water 1 and water 2/3 is very small: 88% compared to 94% and 99% respectively.
3. Watering more than 3 times has no beneficial effect.

There seems to be some truth to the Japanese saying. I will continue watering once day as the difference is too small to be worth my time. However, if I am away for a couple of days, then I will water 3 times to get the maximum amount of water in the pot as possible.

 

[sorce]

Nice!

This is valuable information.

If water is scarce....

Dunking/soaking in a tray can soak things thru to water 2 or 3 or so...

But I would always fresh wash everything thru once 2.

Side note...
Pouring the fish mixture in the drain holes while holding the tree upside Down. Let it soak in. Much less runoff.

Cheers!

Sorce

 

[Michael P]

There is another Japanese saying, "For bonsai it always rains twice." I always follow this during our hot dry summers. In fact, ti sometimes rains three times.

 

[Bonsai Nut]

I decided to test this Japanese saying.

Thank you so much for posting this. On one level, you are standing on very shaky statistical ground. However just the fact that you tested this is cool. It generates hypotheses that could be tested further if someone wished. You are standing on the brink of many "soil wars" threads where people try different watering methods with different soil compositions to see the results.

I have often wondered if we are getting the right answer to the wrong question. Do we really care how much water soil retains if our tree dies? Of course not. So perhaps a different series of tests would be to use the plant clones (cuttings) in the same media, and have different test cases... (1) watering once per day (2) watering twice per day (3) watering three times per day. In a perfect world they would be in a controlled environment (ie greenhouse). Use a large number of cuttings, and maintain the test for a year, and then measure the results in terms of physical characteristics of plant growth (height, width, mass, etc).

Part of the problem with so many of these watering and soil composition threads is the impact of geography and water chemistry. What might work in one location, given heat, humidity, wind, etc, might not work in another. Having just moved from SoCal (hostile plant environment) to North Carolina (grow bonsai on my toes while sleeping on a dock) let me tell you... all water, sun, humidity and wind is not the same

 

[Shibui]

Well done on the trial.
I have come to this through many years of trial and error rather than controlled testing.
Through autopsies on dead trees I found that while the outside of the root ball was wet the inside could be bone dry meaning that a single watering was not penetrating properly.
Wetting new mixed potting soil showed the water wet the top, sides and bottom of the container but did not wet the internal mix.
In both cases, several successive waterings helps the moisture soak in better.
Finally I also found the Japanese water proverb and recognised the accumulated wisdom in it.

While there may be differences between areas and there will be some variation depending on the makeup of the soil there are some things that are constant right round the world. I think water soaking into a potting soil is one of those.

 

[Wires_Guy_wires]

When water touches water, it can draw water from rock through gravitational forces.
Much like how syrup can keep flowing once you turn the bottle upright again; the dangling string of syrup has enough cohesive force to tug a little on the syrup in the bottle.
It would explain why the 4th and 5th watering would have less mass.

Old school siphoning is the same principle and we all know that a bubble can stop the flow entirely; the cohesive forces are blocked.

Nice data collection! Good job.

 

[MrWunderful]

I am going to alter the way I water because of this.
Thanks for doing the experiment.

 

[AZbonsai]

let me tell you... all water, sun, humidity and wind is not the same

Ain't that the truth!

 

[Daniel_UK]

When water touches water, it can draw water from rock through gravitational forces.
Much like how syrup can keep flowing once you turn the bottle upright again; the dangling string of syrup has enough cohesive force to tug a little on the syrup in the bottle.
It would explain why the 4th and 5th watering would have less mass.

Old school siphoning is the same principle and we all know that a bubble can stop the flow entirely; the cohesive forces are blocked.

Nice data collection! Good job.

Thank you for this information - I was baffled by the results on the 4th and 5th watering but you have provided an explanation. If I have understood you correctly then it seems that the water's cohesive force becomes greater than the water's adhesive force to the substrate particles when the water filled porosity has reached its maximum. I would therefore expect the level on future waterings to keep fluctuating slightly as this balancing act plays out.

 

[Wires_Guy_wires]

That's exactly what I meant @Daniel_UK .
I'd expect the same fluctuations.

But I also remember some old gardening books that advise 10 minutes in between watering dry soils. A soil needs some time to absorb water, air needs to get out somehow and in our inorganic soils the air bubbles tend to rise to the outer side preventing water from penetrating.

An old trick is to add a surfactant like dishwashing soap or tween, a tiny drop will break the water tension enough so that a dry soil absorbs it faster. It would also reduce the cohesive force of the water.
Adding a surfactant can reduce the amount of waterings to saturate the soil.
Especially sphagnum moss and potting soil can benefit from that trick.