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2019 marks two years since I got serious about bonsai and started this site.  The first was considerably more focused than the second, but none the less.

I’ve learned a tremendous amount both about bonsai and about blogging.  The largest and most obvious lesson was that both are considerably harder and require more time than you’d think.  But beyond that it’s been an incredible journey.

There is no doubt I’m strongly biased but there were many days I thought maybe bonsai may be the hardest possible topic.  Why?

There’s a long time before you can see your results.  Regardless of if the mystery box ingredient you cooked with is good or terrible or you do it three times, it’s over that evening.  With a bonsai you may not see the results of something you did for weeks, months, or even years.

It’s hard.  This is not 101 material.  Even if it’s easy for you, bonsai is horticulture 201 at the least, if not 301 or 401.  If you can’t keep plants alive to begin with this is not going to work out.  It happens even to professionals that their trees die.

There are a LOT of details.  I can say repot the juniper, or you can get into detail: how deep is the pot you’re potting into, how did you decide what to pot into, why did you choose unglazed, where did you get the screens to put over the holes, demonstrate the technique for bending the wire to affix them, how to wire the tree into the pot, do you soak bottom up or top down and do you provide any sort of vitamins or root boost, and how long do you keep it in shade, what month did you repot if you’re misting afterward how did you rig up your system or how often do you mist… (and on and on).

There are very few absolute correct answers in bonsai.  This is probably the biggest problem.  I’m a perfectionist and feel the quality of my work must be impeccable.  Blogging has been a rewarding exercise because I simply can’t do that.  I tried and I’d never post a word if I everything was just right before I hit publish.  I’m trying to get up to speed on blogging at the same time as bonsai, which seems too much.  But I even see experts contradict one another so I don’t feel so bad.

Two years has brought the first things to my yard that appear somewhat to look like what I would call a quality bonsai tree.  This year significantly less trees have died, so I’m considering that a solid improvement.  Perhaps the biggest thing you learn is actually dozens of little things: I finally created a system to wash my soil mixes.  Found a decent local nursery.  Joined a study group.  Felt greater acceptance in my local bonsai club.  Was able to propagate something and not just kill everything.  Improved my fertilizer regimen.  Lost my fear of bringing my poor quality trees out into the open and in doing so, I believe the quality of my trees improved.

I’m optimistic that starting with this year with a larger number of trees to work with will bring solid progress.  At the least, it can’t get worse.

The post State of the Union: Two Years appeared first on Practical Bonsai.

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We all want the best bonsai soil mix for our trees.  There are two options to getting bonsai soil, mixing your own or buying a packaged bonsai soil mix.  If you buy your own you can buy local or online.

I’ve screened half a dozen popular packaged bonsai soil mixes.  “Best” depends on several factors which I discuss, but two brands ranked an A+ for best bonsai soil.  See the results chart below.

Best bonsai soil testing begins!

Below I show my results and talk about each of these factors.  The factors that make for good bonsai soil include: water retention, pH, cation capacity, product lifecycle, and particle size.

There are no legal standards on what has to be in a package to be called bonsai soil.  Now, there’s plenty of debate about what should be included, and a few things most agree shouldn’t be included.  What all that means is that you can buy a package of “bonsai soil” that’s terrible for your bonsai.  Product reviews aren’t much help here because some beginning hobbyists don’t know enough about bonsai soil mix to understand that what they’re getting is bad.

What are the results?

This review is for the packaged best bonsai soil using GENERAL (vs specialized) ORGANIC (vs inorganic) soil mixes.  Bonsai mix makers will frequently make mixes specifically for conifers or acid loving bonsai or tropicals, etc.  I chose general and organic because it was the most common base to work from.  It’s a bit like if you’re comparing pizza from a bunch of chains, I’m just comparing cheese pizzas only.  If you don’t know if you should be using general vs. specific or organic vs inorganic check out my what bonsai soil should I use article to understand what you’re looking for in a mix.

Basically pH and water retention were similar throughout the mixes, I ranked best bonsai soil mixes based on the percent of usable content in the package, adjusting slightly for two brands.  Without further ado, here are my findings in alphabetical order:

Product Name PB Ranking Reported Contents Cost Source
American Bonsai, Ultra Mix A not disclosed $4.50 per quart, $14.50 per gallon americanbonsai.com
Bonsai Jack A+ pumice, bonsai block (calcined clay), pine fines $17.39 for 2 quarts bonsaijack.com, amazon.com
Brussels Bonsai D not disclosed $15.15 for 2 quarts brusselsbonsai.com, amazon.com
Fujiyama General Purpose Mix C akadama, black lava, pumice, haydite, & charcoal $7.95 for 2 quarts dallasbonsai.com, amazon.com
Green Texan Organic Farms F – – compost, coconut choir, lava sand, lava rock, expanded shale, biochar with EM-1, worm castings $13.99 for 3 quarts amazon.com
Hoffman Bonsai Soil Mix D haydite (expanded shale), sand pebble, aged pine bark, turface $16.08 for 2 quarts amazon.com, walmart.com
Superfly Bonsai A+ 1/3 akadama, 1/3 pumice, 1/3 black lava, & charcoal $15.95 per 1.25 quarts amazon.com, superfly.com
Tiny Roots – All Purpose Blend B pine bark, coarse river sand, horticultural vermiculite, calcine clay, frit $15.95 for 2 quarts amazon.com, bonsaioutlet.com

If you want to hear how I awarded these rankings read on.  You can also scroll down to see the ratings for particle size, pH, and water retention.

Factors Overview

Begin by understanding that I tested only three of the five factors.  The results are mostly based on percentage of usable content as defined by standard plus shohin particle mix with some adjusting thrown in.  Let me explain.

Factors in determining best bonsai soil quality are water retention, pH, cation capacity, product lifecycle, and particle size.  I’ll talk about each of them below.  But for a list of individual components and how they rank you can find data on this nice chart by American Bonsai.

Product Lifecycle (aka Durability)

Product lifecycle is how fast something breaks down.  Some bonsai mix substances naturally breakdown during normal use as a potting medium and others don’t.  Ever.  Organic components naturally break down in time (like pine bark and Akadama) and inorganic components don’t (like lava).  The “best” bonsai soil mixes aren’t either inorganic or organic.  It’s a point of preference and need of the particular bonsai in question.

I didn’t test product lifecycle for two reasons.  These are organic mixes.  Which, by definition, will have components that will break down in time.  Developing a break down rating system starts to get into the discussion of what percent of organic content you want in your soil mix, and that I’m going to stay out of that.  But far more importantly, I can’t think of a practical was to test it at home.  Although even if I did test product lifecycle, the data might not be relevant.  It can take years to break components down and by the time I had the results, the manufacturer might likely change their mix.

Cation Capacity

Cation capacity or cation exchange capacity is how well the soil mix components hold nutrients.  This is important because without much in the way of cation capacity, any fertilizer you give your trees just sort of washes out the bottom.  If you want to hear the science, bonsai expert Adam Lavigne does a nice explanation of what cation capacity is here.  The best bonsai soil mixes need to have some cation exchange capacity to them.  This is one reason the best bonsai soil mix components are raw and jagged, as opposed to tumbled smooth and finished.

I didn’t test for cation capacity because I don’t know of a nice home method to test for it.  If you have any suggestions please let me know.

pH

pH is how acid or alkaline a soil mix is.  Some plants like a slightly acidic or alkaline soil mix (for example azaleas like acidic soil).  But most plants and bonsai stay close to a neutral 7, or a soil mix that is very slightly acidic.  Lower numbers are more acidic and higher numbers are more alkaline.  The best bonsai soil packaged mixes will have a pH of 7 or possibly around 6.5.  If you are looking for something more acidic you’ll either get it from a special mix or by using an acidic fertilizer.

pH testing on bonsai soil samples.

I tested pH for all the soil mixes as well as diatomaceous earth, red lava, and pine bark.  Methodology wise I took a cup of soil for both the standard mix and the fines of each mix.  They were flooded with distilled water, and I waited until the water permeated the mix.  After waiting for the water to permeate, I removed excess water, and gently tamped down the remaining mix.

Everything was tested with two different home pH meters.  I tested with each meter in two different spots in the soil, and left each meter in for a full 60 seconds as directed by product instructions.  The instruments were cleaned before moving from one mix to another.

The results were that pH for everything ranked within a point of neutral pH of 7.  The only mix that was irregular in any fashion was Green Texan, which showed wildly ranging pH readings as the probe moved through the soil mix.  Even with this mix though I took ratings based only on the end reading once the probes were still for 60 seconds (or longer).

For purposes of this review I concluded that the mixes were all within neutral readings, and pH did not alter anyone’s score.

Product Name American Bonsai Bonsai Jack Brussels Bonsai Fujiyama Green Texan Hoffman Superfly Tiny Roots DE red lava pine bark
pH fines 1 prong 6.80 NA 7.00 6.70 7.00 7.00 NA 6.40 NA NA NA
7.00 NA 7.00 7.00 6.80 7.00 NA 6.50 NA NA NA
ph fines 2 prong 7.75 NA 8.00 7.00 8.00 7.75 NA 7.75 NA NA NA
8.00 NA 7.75 6.50 7.75 7.75 NA 6.50 NA NA NA
ph standard 1 prong 7.00 7.00 7.00 7.00 7.00 7.00 7.00 7.00 7.00 7.00 7.00
7.00 7.00 7.00 7.00 4.60 7.00 7.00 7.00 7.00 7.00 7.00
ph standard 2 prong 7.75 8.00 8.00 7.75 8.00 7.75 8.00 7.75 7.25 8.00 7.50
7.50 8.00 8.00 7.25 4.56 7.75 8.00 7.50 7.50 7.75 7.50
standard average 7.31 7.50 7.50 7.25 6.04 7.38 7.50 7.31 7.19 7.44 7.25
Average 7.35 7.50 7.47 7.03 6.71 7.38 7.50 7.05 7.19 7.44 7.25
Average plus or minus 1 7.00 7.50 7.50 7.00 6.50 7.50 7.50 7.00 7.00 7.50 7.50
Water Retention

Water retention is how well your soil mix stores water for the plant to use later.  Lets say you soaked with water one cup full of mulch, and a second with glass marbles and then dumped out all the water.  Both components would be wet.  But after a short time the marbles will be dry and the mulch would stay wet.  That is because bark holds water and glass doesn’t.  This is the same reason world class bonsai aren’t all potted in cheap, evenly sized, pH neutral fish tank rocks.  Because, like marbles, they’d get wet but not hold any water.  The best bonsai soil mix will let a bonsai’s roots not sit in water, but also be able to access water when it needs it.  Without water retention in a soil mix your bonsai will die.

Testing bonsai soil water retention.

For water retention I filled a cup with standard sized particles from each mix.  I also tested fish rocks as a control, and some individual components as a point of reference.  I soaked each mix in distilled water then drained out excess water.  Then I waited.  Each day for a week at the same time I checked the moisture level with both a moisture meter and by hand.  At times the moisture meter read dry when my hands said it was moist or wet.  But sometimes it was the reverse.

Of the mixes, Bonsai Jack, American Bonsai, and Brussels ran dry.  Superfly and Green Texan ran wet.  Hoffman, Tiny Roots, and Fujiyama ran the middle, staying moist.  None of the mixes rated completely dry like the control.  I didn’t penalize or advance anyone for water retention because this can be a point of preference.

Particle Size

Particle size is simply how big the soil mix particles are.  The best bonsai soil mixes will have particles that are fairly consistent in size and not too big or small.  That will give your bonsai access to both water and nutrients but also to oxygen.  Particles that are too small can make your mix too wet and rot your roots.  Though screening alone is elementary, I don’t hesitate to rank based on this almost exclusively because it’s very important.  Below is a picture of the best and worst ranked soil mixes straight out of the package.  The best bonsai soil mixes should look like the mix on the left – like a bunch of small rocks.  In the picture, the mix on the right looks more like potting soil and is not what you want.

Sieving was done with a basic personal bonsai sieve set.  The sizes used were 0.25 and 0.10 inches. Particles larger than the largest filter set size are “too big,” particles between the largest and smallest size are “standard.”  I add another level with a basic kitchen sieve for the “shohin” and the unscientific note that the filter size is just a bit smaller than the last size.  What goes through is dust or “fines.”  All measurements are in cups.

Product Name American Bonsai Bonsai Jack Brussels Bonsai Fujiyama Green Texan Hoffman Superfly Bonsai Tiny Roots
Total Product 15.50 8.00 9.66 9.00 13.00 9.66 5.50 7.33
Too large 1.50 0.13 0.50 0.66 0.50 1.50 0.00 0.13
9.7% 1.6% 5.2% 7.3% 3.8% 15.5% 0.0% 1.7%
Standard 12.25 7.66 6.66 5.00 3.00 5.33 5.00 4.00
79.0% 95.8% 68.9% 55.6% 23.1% 55.2% 90.9% 54.6%
Shohin 1.66 0.03 1.00 1.66 1.25 1.33 0.25 2.50
10.7% 0.4% 10.4% 18.4% 9.6% 13.8% 4.5% 34.1%
Fines 1.00 0.03 1.50 2.66 8.06 2.33 0.13 1.00
6.5% 0.4% 15.5% 29.6% 62.0% 24.1% 2.3% 13.6%
standard + shohin 89.7% 96.1% 79.3% 74.0% 32.7% 68.9% 95.5% 88.7%
Rankings

The majority factor in ranking best packaged bonsai soil mix is the percentage of usable content.  There’s two reasons for that.  With traditional bonsai soil, components that are too small (fines) are considered garbage by many hobbyists.  So if 25% of the material you buy is garbage, it changes what you think you’re buying.  If I lived in an apartment and didn’t garden I’d throw the fines in the trash.  Some larger components can be broken down, but that depends on what they’re made of.  Also that takes more work and simply isn’t what you agreed to buy.

Particle size is also fairly objective.  Though how you define “large” and “small” might vary, and large particles can be seen as a quarter cup more or less, aside from that it’s pretty black and white.  It’s true that any one of these mixes could have been a bad batch.  But then the company would have had to let out a bad batch, which could just as well be yours.

I gave all the mixes the benefit of the doubt and counted both standard sized particles PLUS shohin or small sized particles as usable content.  Some soil manufacturers make a specific mix for shohin for small bonsai.  By far this is the honorable way to go.  Quality should be rewarded, which is why I made my A+ rating.  I wouldn’t bother to sieve something with 2% fines.  With 10% fines I absolutely wo.

In general, calling standard plus shohin sized components “usable” I rankulded the mixes as:

  • A+ : 95% + usable content and 5% or less fines
  • A:  90-95% usable content
  • B:  80-89% usable content
  • C:  70-79% usable content
  • D: 60-69% usable content
  • F: 50-59% usable content

I didn’t alter anyone’s score because of pH or water retention rankings.

Exceptions

I did though alter my overall ranking for two mixes:

American Bonsai was bumped up to an A.  They had 89.7% usable content.  However, their 9.7% too large particles were just a hair too large.  I have no doubt that they sieve, their sieves are just a touch larger than mine.  Adding those too large particles actually puts their usable content at 95% plus, but they had 6% fines, so they remain an A.

Brussels Bonsai was bumped down from a C to a D.  It was the only mix that I opened and clearly smelled fertilizer.  It looked a lot like fertilizer too, and it was more like sieving out dirt from the bonsai components than sieving large from small bonsai components.

Discretion is important here because there are some things that just don’t translate into numbers.  For example, in the image below shows the “too large” particles that didn’t sieve through for two different brands.  American Bonsai’s particles were just a hair too big, most people wouldn’t even notice.  Hoffman’s particles were much too big, like orchid bark.

Testing Notes

I selected mixes based on what is commonly available (Amazon, Walmart, three of the top bonsai retailers, and one popular company).  These mixes probably compose at least 75% of the bonsai soil sold online.

This review is testing for best bonsai soil and not pre-bonsai soil.  There are a lot of mixes people use for pre-bonsai or in training boxes.  Compost can be an excellent medium to grow plants, but the particles are too small for a bonsai mix.  I’d say compost is a pre-bonsai component, not a component for quality bonsai soil mix.

One note of fairness, all the soils I purchased within 30 days of testing them, except American Bonsai.  I had purchased their soil with some tools almost a year before.  Their mix tested very good, but missed the A+ because of the dustiness.  Probably if I had bought this mix within 30 days of sieving like the others, it would be less dusty.  Also on this note of fairness, American Bonsai had an additional 2 tablespoons of fines in the package between the burlap and the plastic that I did not count to their total as the packaging itself sieved it out.

Why do the columns not add up to the whole?

The columns don’t add up to the whole volume because I separated the parts and measured them.  You may have heard the analogy about the person who has pebbles in a jar and tries to put in large rocks, and can’t.  But if that person dumps those small pebbles out and first puts in the large rocks, and then puts in the pebbles, then they can get them all in.  And also sand, and then water.  When you sieve the mixes and measure the components seperately, basically you’re..

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We all want the best bonsai soil mix for our trees.  There are two options to getting bonsai soil, mixing your own or buying a packaged bonsai soil mix.  If you buy your own you can buy local or online.

I’ve screened half a dozen popular packaged bonsai soil mixes.  “Best” depends on several factors which I discuss, but two brands ranked an A+ for best bonsai soil.  See the results chart below.

Best bonsai soil testing begins!

Below I show my results and talk about each of these factors.  The factors that make for good bonsai soil include: water retention, pH, cation capacity, product lifecycle, and particle size.

There are no legal standards on what has to be in a package to be called bonsai soil.  Now, there’s plenty of debate about what should be included, and a few things most agree shouldn’t be included.  What all that means is that you can buy a package of “bonsai soil” that’s terrible for your bonsai.  Product reviews aren’t much help here because some beginning hobbyists don’t know enough about bonsai soil mix to understand that what they’re getting is bad.

What are the results?

This review is for the packaged best bonsai soil using GENERAL (vs specialized) ORGANIC (vs inorganic) soil mixes.  Bonsai mix makers will frequently make mixes specifically for conifers or acid loving bonsai or tropicals, etc.  I chose general and organic because it was the most common base to work from.  It’s a bit like if you’re comparing pizza from a bunch of chains, I’m just comparing cheese pizzas only.  If you don’t know if you should be using general vs. specific or organic vs inorganic check out my what bonsai soil should I use article to understand what you’re looking for in a mix.

Basically pH and water retention were similar throughout the mixes, I ranked best bonsai soil mixes based on the percent of usable content in the package, adjusting slightly for two brands.  Without further ado, here are my findings in alphabetical order:

Product Name PB Ranking Reported Contents Cost Source
American Bonsai, Ultra Mix A not disclosed $4.50 per quart, $14.50 per gallon americanbonsai.com
Bonsai Jack A+ pumice, bonsai block (calcined clay), pine fines $17.39 for 2 quarts bonsaijack.com, amazon.com
Brussels Bonsai D not disclosed $15.15 for 2 quarts brusselsbonsai.com, amazon.com
Fujiyama General Purpose Mix C akadama, black lava, pumice, haydite, & charcoal $7.95 for 2 quarts dallasbonsai.com, amazon.com
Green Texan Organic Farms F – – compost, coconut choir, lava sand, lava rock, expanded shale, biochar with EM-1, worm castings $13.99 for 3 quarts amazon.com
Hoffman Bonsai Soil Mix D haydite (expanded shale), sand pebble, aged pine bark, turface $16.08 for 2 quarts amazon.com, walmart.com
Superfly Bonsai A+ 1/3 akadama, 1/3 pumice, 1/3 black lava, & charcoal $15.95 per 1.25 quarts amazon.com, superfly.com
Tiny Roots – All Purpose Blend B pine bark, coarse river sand, horticultural vermiculite, calcine clay, frit $15.95 for 2 quarts amazon.com, bonsaioutlet.com

If you want to hear how I awarded these rankings read on.  You can also scroll down to see the ratings for particle size, pH, and water retention.

Factors Overview

Begin by understanding that I tested only three of the five factors.  The results are mostly based on percentage of usable content as defined by standard plus shohin particle mix with some adjusting thrown in.  Let me explain.

Factors in determining best bonsai soil quality are water retention, pH, cation capacity, product lifecycle, and particle size.  I’ll talk about each of them below.  But for a list of individual components and how they rank you can find data on this nice chart by American Bonsai.

Product Lifecycle (aka Durability)

Product lifecycle is how fast something breaks down.  Some bonsai mix substances naturally breakdown during normal use as a potting medium and others don’t.  Ever.  Organic components naturally break down in time (like pine bark and Akadama) and inorganic components don’t (like lava).  The “best” bonsai soil mixes aren’t either inorganic or organic.  It’s a point of preference and need of the particular bonsai in question.

I didn’t test product lifecycle for two reasons.  These are organic mixes.  Which, by definition, will have components that will break down in time.  Developing a break down rating system starts to get into the discussion of what percent of organic content you want in your soil mix, and that I’m going to stay out of that.  But far more importantly, I can’t think of a practical was to test it at home.  Although even if I did test product lifecycle, the data might not be relevant.  It can take years to break components down and by the time I had the results, the manufacturer might likely change their mix.

Cation Capacity

Cation capacity or cation exchange capacity is how well the soil mix components hold nutrients.  This is important because without much in the way of cation capacity, any fertilizer you give your trees just sort of washes out the bottom.  If you want to hear the science, bonsai expert Adam Lavigne does a nice explanation of what cation capacity is here.  The best bonsai soil mixes need to have some cation exchange capacity to them.  This is one reason the best bonsai soil mix components are raw and jagged, as opposed to tumbled smooth and finished.

I didn’t test for cation capacity because I don’t know of a nice home method to test for it.  If you have any suggestions please let me know.

pH

pH is how acid or alkaline a soil mix is.  Some plants like a slightly acidic or alkaline soil mix (for example azaleas like acidic soil).  But most plants and bonsai stay close to a neutral 7, or a soil mix that is very slightly acidic.  Lower numbers are more acidic and higher numbers are more alkaline.  The best bonsai soil packaged mixes will have a pH of 7 or possibly around 6.5.  If you are looking for something more acidic you’ll either get it from a special mix or by using an acidic fertilizer.

pH testing on bonsai soil samples.

I tested pH for all the soil mixes as well as diatomaceous earth, red lava, and pine bark.  Methodology wise I took a cup of soil for both the standard mix and the fines of each mix.  They were flooded with distilled water, and I waited until the water permeated the mix.  After waiting for the water to permeate, I removed excess water, and gently tamped down the remaining mix.

Everything was tested with two different home pH meters.  I tested with each meter in two different spots in the soil, and left each meter in for a full 60 seconds as directed by product instructions.  The instruments were cleaned before moving from one mix to another.

The results were that pH for everything ranked within a point of neutral pH of 7.  The only mix that was irregular in any fashion was Green Texan, which showed wildly ranging pH readings as the probe moved through the soil mix.  Even with this mix though I took ratings based only on the end reading once the probes were still for 60 seconds (or longer).

For purposes of this review I concluded that the mixes were all within neutral readings, and pH did not alter anyone’s score.

Product Name American Bonsai Bonsai Jack Brussels Bonsai Fujiyama Green Texan Hoffman Superfly Tiny Roots DE red lava pine bark
pH fines 1 prong 6.80 NA 7.00 6.70 7.00 7.00 NA 6.40 NA NA NA
7.00 NA 7.00 7.00 6.80 7.00 NA 6.50 NA NA NA
ph fines 2 prong 7.75 NA 8.00 7.00 8.00 7.75 NA 7.75 NA NA NA
8.00 NA 7.75 6.50 7.75 7.75 NA 6.50 NA NA NA
ph standard 1 prong 7.00 7.00 7.00 7.00 7.00 7.00 7.00 7.00 7.00 7.00 7.00
7.00 7.00 7.00 7.00 4.60 7.00 7.00 7.00 7.00 7.00 7.00
ph standard 2 prong 7.75 8.00 8.00 7.75 8.00 7.75 8.00 7.75 7.25 8.00 7.50
7.50 8.00 8.00 7.25 4.56 7.75 8.00 7.50 7.50 7.75 7.50
standard average 7.31 7.50 7.50 7.25 6.04 7.38 7.50 7.31 7.19 7.44 7.25
Average 7.35 7.50 7.47 7.03 6.71 7.38 7.50 7.05 7.19 7.44 7.25
Average plus or minus 1 7.00 7.50 7.50 7.00 6.50 7.50 7.50 7.00 7.00 7.50 7.50
Water Retention

Water retention is how well your soil mix stores water for the plant to use later.  Lets say you soaked with water one cup full of mulch, and a second with glass marbles and then dumped out all the water.  Both components would be wet.  But after a short time the marbles will be dry and the mulch would stay wet.  That is because bark holds water and glass doesn’t.  This is the same reason world class bonsai aren’t all potted in cheap, evenly sized, pH neutral fish tank rocks.  Because, like marbles, they’d get wet but not hold any water.  The best bonsai soil mix will let a bonsai’s roots not sit in water, but also be able to access water when it needs it.  Without water retention in a soil mix your bonsai will die.

Testing bonsai soil water retention.

For water retention I filled a cup with standard sized particles from each mix.  I also tested fish rocks as a control, and some individual components as a point of reference.  I soaked each mix in distilled water then drained out excess water.  Then I waited.  Each day for a week at the same time I checked the moisture level with both a moisture meter and by hand.  At times the moisture meter read dry when my hands said it was moist or wet.  But sometimes it was the reverse.  One factor there is that my soil samples were in standard solo cups.  That shape is more like a cascade bonsai pot than a standard bonsai pot.  It will logically dry out slower on the bottom.  Fairly quickly, moisture levels at the top and bottom would be different.  Here are the results.

Product Name American Bonsai Bonsai Jack Brussels Bonsai Fujiyama Green Texan Hoffman Superfly Bonsai Tiny Roots DE red lava pine bark pumice fish rocks
D1, M1 6.5 2.0 5.0 6.0 8.5 7.5 6.5 8.0 9.0 1.0 1.0 1.0 0.5
D1, M2 5.0 3.0 3.0 6.5 9.0 7.5 7.0 8.0 10.0 0.5 1.5 1.0 0.5
Average 5.8 2.5 4.0 6.3 8.8 7.5 6.8 8.0 9.5 0.8 1.3 1.0 0.5
D1, T wet wet wet wet wet wet wet wet wet wet wet wet wet
D2, M1 5.5 4.0 3.0 6.0 8.5 6.5 4.0 7.0 9.5 1.0 1.0 0.5 0.5
D2, M2 6.5 2.5 3.0 6.5 9.0 7.5 3.5 7.0 10.0 0.5 1.0 0.5 0.5
Average 6.0 3.3 3.0 6.3 8.8 7.0 3.8 7.0 9.8 0.8 1.0 0.5 0.5
D2, T moist/dry moist/dry moist wet wet moist wet wet wet wet wet wet dry
D3, M1 5.0 4.0 2.5 5.0 7.5 5.5 4.0 7.0 9.0 1.0 1.0 0.5 0.5
D3, M2 6.0 1.0 1.0 5.5 8.5 3.0 4.5 7.5 9.5 1.0 1.0 0.5 0.5
Average 5.5 2.5 1.8 5.3 8.0 4.3 4.3 7.3 9.3 1.0 1.0 0.5 0.5
D3, T moist/dry dry dry wet / moist wet moist wet moist wet wet moist wet dry
D4, M1 3.5 2.5 1.5 5.5 9.5 4.0 2.0 7.0 9.5 0.5 0.5 0.5 0.5
D4, M2 5.0 1.5 2.5 6.5 9.0 4.0 3.0 7.0 9.0 0.5 1.0 0.5 0.5
Average 4.3 2.0 2.0 6.0 9.3 4.0 2.5 7.0 9.3 0.5 0.8 0.5 0.5
D4, T dry dry dry moist wet moist wet moist wet wet moist wet dry
D5, M1 3.0 1.0 1.5 4.0 6.0 4.0 2.0 7.0 9.0 0.5 1.0 0.5 NA
D5, M2 2.5 2.0 1.0 4.0 9.0 5.0 2.0 8.0 9.0 0.5 1.0 0.5 NA
Average 2.8 1.5 1.3 4.0 7.5 4.5 2.0 7.5 9.0 0.5 1.0 0.5
D5, T dry dry dry moist moist dry wet moist wet moist dry wet NA
D6, M1 2.0 1.0 2.5 3.0 4.5 3.0 1.0 6.0 4.0 0.5 0.5 0.5 NA
D6, M2 3.0 0.5 1.0 3.0 4.0 2.5 1.5 5.5 6.5 0.5 0.5 0.5 NA
Average 2.5 0.8 1.8 3.0 4.3 2.8 1.3 5.8 5.3 0.5 0.5 0.5
D6, T dry dry dry moist wet dry wet moist wet moist dry moist NA
D7, M1 1.0 1.0 1.0 1.5 5.0 1.0 1.0 5.0 5.0 0.5 1.0 0.5 NA
D7, M2 1.5 1.0 1.0 3.0 5.5 1.5 1.0 4.5 4.5 0.5 0.5 0.5 NA
Average 1.3 1.0 1.0 2.3 5.3 1.3 1.0 4.8 4.8
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