Lava vs pumice vs leca soil test

[YAN]

Hello all, I’m new here and to bonsai in general, i did play with some nursery stocks but nothing serious, I read a lot and what I understood is that roots are one of if not the most important part of bonsai and the idea of not being able to visually observe what’s going on in there worries us beginners.
When thinking roots first thing comes to mind is soil, again researched a lot and came across a thread here by markyscott “introductory soil physics” ( i want to thank him and all who shared their knowledge in that thread), so i wanted to test some soils i can find readily and locally with the methods Scott used for his experiment for next spring repotting.
Some notes :
- i can water only once a day in the early morning (max)
- inorganic as much as possible.
- my climate: Mediterranean, 4 seasons, very humid, 5C~ winter 32C~ summer, distance: 5km from sea, 500m above sea level.
- tree sizes: Shohin outdoor, shohin and mame indoor.
- no access to decent organic fertilizers but many inorganic liquids.
- to much rain in winter.
- access to: lava rock, pumice, perlite, leca (balls) and pine bark if needed for water retention.
- I excluded perlite for bad experience ( floating, color etc...)
- all aggregates are crushed and sieved specially LECA balls have smooth outer shell and very hard to absorb water if not crushed.
- pot size 9x4 cm, 190 ml volume of soil.

 

[Leo in N E Illinois]

Clearly, pumice holds more water than the other two.

Lava and leca are close, and have more air filled porosity.

So if your pots are not holding enough water, add more pumice to the mix.
If your pots are staying wet too long, add more lava to the mix.

Leca is a pretty good material, more like lava than pumice in water holding and air holding capacity.

At least that is my take on your well constructed comparison.

Thank you for doing a set of good measurements.

 

[Trenthany]

Hello all, I’m new here and to bonsai in general, i did play with some nursery stocks but nothing serious, I read a lot and what I understood is that roots are one of if not the most important part of bonsai and the idea of not being able to visually observe what’s going on in there worries us beginners.
When thinking roots first thing comes to mind is soil, again researched a lot and came across a thread here by markyscott “introductory soil physics” ( i want to thank him and all who shared their knowledge in that thread), so i wanted to test some soils i can find readily and locally with the methods Scott used for his experiment for next spring repotting.
Some notes :
- i can water only once a day in the early morning (max)
- inorganic as much as possible.
- my climate: Mediterranean, 4 seasons, very humid, 5C~ winter 32C~ summer, distance: 5km from sea, 500m above sea level.
- tree sizes: Shohin outdoor, shohin and mame indoor.
- no access to decent organic fertilizers but many inorganic liquids.
- to much rain in winter.
- access to: lava rock, pumice, perlite, leca (balls) and pine bark if needed for water retention.
- I excluded perlite for bad experience ( floating, color etc...)
- all aggregates are crushed and sieved specially LECA balls have smooth outer shell and very hard to absorb water if not crushed.
- pot size 9x4 cm, 190 ml volume of soil.View attachment 322132View attachment 322133View attachment 322134View attachment 322135View attachment 322136View attachment 322137View attachment 322138View attachment 322139

Did you fill and drain immediately or let them soak? This will effect your results but I love the comparisons! I’m saving them for my own use!

 

[YAN]

Tha

Clearly, pumice holds more water than the other two.

Lava and leca are close, and have more air filled porosity.

So if your pots are not holding enough water, add more pumice to the mix.
If your pots are staying wet too long, add more lava to the mix.

Leca is a pretty good material, more like lava than pumice in water holding and air holding capacity.

At least that is my take on your well constructed comparison.

Thank you for doing a set of good measurements.

That was my observation too but I’m having hard time to deside what particle size to go with, More tests are on the way outdoors under full sun with the same samples.

 

[Trenthany]

Tha

That was my observation too but I’m having hard time to deside what particle size to go with, More test are on the way outdoors under full sune with the same samples.

Can’t wait!

 

[YAN]

Did you fill and drain immediately or let them soak? This will effect your results but I love the comparisons! I’m saving them for my own use!

I soaked them about 4-5 minutes, lava and leca absorbed immediately but pumice needed more water after 3 minutes as the water level decreased

 

[Anthony]

Yan,

try the lecca at 6 mm 7 parts, with around 3 parts or less compost.
Grow something.

Talk to Mr. Walter Pall - member here,

Look up the Ball - Bearing Principle.

Your refining pots may only need to be 8 cm deep.
Good Day
Anthony

 

[Trenthany]

I soaked them about 4-5 minutes, lava and leca absorbed immediately but pumice needed more water after 3 minutes as the water level decreased

Interesting! I may do my own version in a draining pot with watering through the soil to see how much is absorbed during spray watering vs submersion watering.

 

[YAN]

Tha

Yan,

try the lecca at 6 mm 7 parts, with around 3 parts or less compost.
Grow something.

Talk to Mr. Walter Pall - member here,

Look up the Ball - Bearing Principle.

Your refining pots may only need to be 8 cm deep.
Good Day
Anthony

Thank you,
Sure I’ll try some cheap plants in several mixes

 

[YAN]

Interesting! I may do my own version in a draining pot with watering through the soil to see how much is absorbed during spray watering vs submersion watering.

I thaught about that, but i had to soak them to have a precise total porosity number.
For the incoming test i let it completely dry then watered like i would normally water everyday (spray watering) don’t worry.

 

[Trenthany]

I thaught about that, but i had to soak them to have a precise total porosity number.
For the incoming test i let it completely dry then watered like i would normally water everyday (spray watering) don’t worry.

Perfect! Just going to put them on your bench and pretend there are trees in them? Lol I would pick a set time to weigh so that they’re drained out. Maybe 10 minutes etc.

 

[YAN]

Perfect! Just going to put them on your bench and pretend there are trees in them? Lol I would pick a set time to weigh so that they’re drained out. Maybe 10 minutes etc.

Yes but this will not be an accurate test by any means as tree will suck even more water (if it existed) so this is solely evaporation test.
Didn’t understand second part.

 

[Trenthany]

Yes but this will not be an accurate test by any means as tree will suck even more water (if it existed) so this is solely evaporation test.
Didn’t understand second part.

Weigh them for water absorption? See how much they retain through this method of watering. Submersion watering may be significantly more helpful and this might give us a percentage of how much compared to watering until it’s flowing out the bottom steadily.

 

[YAN]

Weigh them for water absorption? See how much they retain through this method of watering. Submersion watering may be significantly more helpful and this might give us a percentage of how much compared to watering until it’s flowing out the bottom steadily.

I did 3 rounds of watering as i do usually with all trees and weighted the same as submersion, i was surprised but that was the result and yes i let it dry for 3 days and weighted the same as dry before i start the whole experiment.

 

[Trenthany]

I did 3 rounds of watering as i do usually with all trees and weighted the same as submersion, i was surprised but that was the result and yes i let it dry for 3 days and weighted the same as dry before i start the whole experiment.

Very cool! Those tables of yours will have immense use in planning soil composition for various watering practices.

 

[YAN]

So i let all samples dry for 3 days under full sun and made sure it was completely dry by weighting them.

Next i watered them for 3 rounds as I usually do (what almost every pro bonsai artists do) and let it drain then put them back under full sun and weighted them every hour for 24 hours, i watered at 8:00 am and last weighted them next morning at 8:00 am.

I skipped weighting from 11:00 pm till 6:00 am because there wasn’t any noticeable changes after sunset and to get some sleep obviously.

This experiment is solely a test for water evaporation of different aggregates under same conditions of weather, sun, humidity, wind etc...

things to consider that this experiment doesn’t include:
- water absortion of tree.
- CEC (cation-exchange capacity) of soil.
- macro and micro nutrients of soil.
- (wilting point) even if some water is present it is no longer available to the tree.
- decomposition ( although samples used here are impossible/very hard to decompose ).

 

[Anthony]

Yan,

it takes 3 to 5 years to learn how to water Bonsai.
Good Day
Anthony

 

[YAN]

Yan,

it takes 3 to 5 years to learn how to water Bonsai.
Good Day
Anthony

So i still have 3 to 5 years left to learn.
Sure, I’m just imitating what pros do.
I’ve heard some Japanese bonsai masters are still learning to water

 

[Alain BERTRAND]

That's interesting. I did that kind of study when I started doing bonsai seriously and the pumice I can buy here has always about 10 % porosity less than lava, probably because of its rounder shape. As you probably know, the ration air/water filled porosity varies with the height of the pot.

 

[YAN]

That's interesting. I did that kind of study when I started doing bonsai seriously and the pumice I can buy here has always about 10 % porosity less than lava, probably because of its rounder shape. As you probably know, the ration air/water filled porosity varies with the height of the pot.

Tru

i think for more accurate results test must be done in the same/identical pot the tree is going in.