Bonsai Soil Tests: Part 1: Water Retention

Bonsai Soil Tests: Part 1: Water Retention


Welcome to Appalachian Bonsai. This video is one of a series to discuss soil components and some of their properties as they pertain to bonsai. These components are what we’re available to me at this particular time. What’s available to you may vary by region or by country. When it comes to bonsai soil no two person’s soil mixtures are alike. Each soil mixture depends upon the species, the climate, and the person who’s using them. I hope that just seeing these components in testing will allow you to make choices for your own. Thanks for watching. Today, we’re going to look at water retention and a little bit on drainage. All plants need water so let’s see how much water these components hold. Both organic and inorganic materials were considered. Just because something holds moisture doesn’t make it good. Conversely, just because it might not absorb moisture doesn’t make it bad. I began by measuring equal volumes of each component and measured their dry weight for reference. Next, I added distilled water to each type and let it soak for one hour. This should allow plenty of time for each type of soil to fully saturate. After an hour, the components are removed from the water and allowed to drain. Each is weighed out over time to calculate retention. Let’s see the differences. We’ll begin with organic materials. Coconut coir is commonly used in flower baskets and hydroponics. It is sold in brick form and soaks up water like a sponge. It fills the entire cup. That’s a lot of water! But, all available space is filled, which isn’t necessarily good for bonsai. We’ll will look more on that type of drainage in another video. After draining for an hour and 45 minutes, we weighed each sample. We weighed the samples again 3.5 hours later. By comparing the different weights, we are able to determine the amount of water retained, and a basic percentage of loss. At 129 grams of water retained, plus minimal loss, Coconut Coir ranks number one in organic material water retention. This is mushroom compost I bought in bags at my local nursery. It is damp at purchase time, so I oven-dried it before I used it. Small twigs and sand may be present, and the content will vary depending on where you purchase. It drains well and has a slight alkalinity.
I’ll do a video on pH at a later date. At 26 grams of water retained and 31.5% lost, Compost comes in at number three with water retention for organic material. Sphagnum moss is found in cooler damper regions of the world and is known to hold moisture very well. However, in the United States commercially available peat moss comes in a fine kiln dry powder. Unlike fresh sphagnum. In this processed form it does not whet easily,
much like baking flour. More information will be available in a future video. You can see it has absorbed very little water,
and is actually floating on top. If powdered peat moss in a soil mix is allowed to dry out potential dead zones may occur. If it is saturated, powdered peat moss
will hold plenty of moisture, but for this test, it did not perform well. After draining for five and a quarter hour, peat moss only held six grams of water with 40% loss. It ranks number four on the organic list. Pine bark and fir bark are fan favorites in the bonsai world. I have pine bark available in my region. Here, pine bark chips can be sold as soil conditioner. I sift it to a proper size and put the rest in the garden. Sifted bark drains well and holds good moisture. Beneficial microorganisms like bacteria can thrive in these porous structures. As a quick note, pine bark is on the acidic side. At retaining 22 grams of water at a 14.8% loss, pine bark comes in at number two in organic water retention. Let’s look at the Inorganic materials and aggregates. Akadama is the classic gold standard of Japanese bonsai mixtures. Here in most of the U.S., it is expensive and not readily available. It is often purchased online or at dedicated bonsai nurseries. Its large particle size drains well and its porosity absorbs and retains moisture. Because of the expense and its scarcity outside of Japan, people around the world look for alternatives to akadama. With water retention of 22 grams at a 26.6% loss, Akadama ranks number two overall in inorganic material. Diatomaceous Earth, or diatomite, is a lightweight fossilized clay that is used as an absorbent in kitty litter and oil dry. This product needs to be sifted well before use. It also compacts and breaks down over time.
We will look at that in another video. Like Akadama, it absorbs and retains moisture very well, and in fact, retains more water than akadama. At 37 grams of water retained with 30% loss, Diatomaceous Earth comes in at number one overall ranking, Chicken grit or granite chips is a popular aggregate in soil mixtures. Its popularity stems from its excellent drainage, its inert structure, and it’s pretty cheap. It’s also one of the heaviest components used. The color depends on the quarry, and for the most part is non-porous and absorbs little water. Most of the water retained is merely from surface tension. With only one gram of water retained and a 94.4% loss, Granite chips ranked last in our list of inorganic materials. Expanded shale is becoming more available as a soil component because of its ability to prevent compaction. It has a semi porous structure and can absorb some moisture. The large particle size I had available to me drains very well. It has a good color, too. Unlike some other expanded materials this one does not break down easily over time. With only two grams of water and 84.6% loss Expanded shale ranks number nine on the inorganic list. Lava-Rock, which is sometimes known as scoria, is a hard yet porous material with excellent drainage. Its large pores absorb some moisture and can house beneficial bacteria. It also has a pretty color which makes it a good choice for top dressing. Similar to expanded shale and granite, it can last a long time without breaking down. But 4 grams of water at 76% loss, Lava Rock or Scoria ranks number eight overall in inorganic material. Perlite is a type of volcanic glass that is expanded with high heat. It is common in growing mediums here in the U.S. Its porous structure allows it to float. Much like lava rock and granite, most of the water retained is through surface tension. Also like these other components, It does not break down easily over time One of the problems for bonsai is its stark white color. This usually means it’s only used for training trees and not for formal presentations. At 14 grams of water and 36% loss this product ranks number six on our list. Pumice is a less dense, but more porous variety of Lava Rock. It, like processed perlite, will float. Like nearly all materials that you use in bonsai, you need to make sure that you sift it and wash it well before you use it. It drains well, and it’s similar to Akadama and its ability to hold and retain good moisture. With 22 grams of water retained and only 29% loss, Pumice holds the number three rank for inorganic material. Sand is one of the most available components around the world. It’s also the heaviest of the components that we tested. Small grains of sand can easily block drainage, so it must be sifted well before use. Sand also drains very well, but the majority of the moisture held within it is from surface tension and not from absorption. With 12 grams of moisture retained in 67.5% loss,
Sand ranks number seven on our list. Turface is a type of Lightweight Expanded Clay Aggregate or L.E.C.A. It is one of the most common Bonsai soil mediums used outside of Japan. It readily absorbs moisture, but like all of these components, it does have some drawbacks that will be discussed later in another video. Turface drains well and has a very good color. Though it’s relatively stable, it can break down over time. Turface held 30 grams of water with 36% loss. This ranks at number 4 on our Inorganic list. Vermiculite is sold in various forms, including this expanded type. It’s most common use in the gardening world is to break up clay soils. Its use in bonsai depends upon the person. Even though it floats along the surface it does absorb moisture without becoming soggy. There is potential for vermiculite’s small size to clog drainage. Because of its 28 grams of retention with 41.6% loss, Vermiculite comes in at number five. Bees. Again, this is not a full list of components used for bonsai soil mixtures, but what we’re available to me at this time. I have more tests to show you so stick around. Leave a comment in the section below about what types of tests you’d like to see me perform in the future. If you haven’t already,
Follow us on Facebook or Instagram Stay tuned… There’s always more to come! Thanks for watching!! [Bluegrass music]

99 thoughts on “Bonsai Soil Tests: Part 1: Water Retention

  1. Great video and test! (And glasses!) My only suggestion would be to include a sort of summary at the end, perhaps just the numbered lists of which materials held the most water in each category.

  2. you should update one of you trees every video like nigel saunders does its show the progression of your trees nicely

  3. Napa 8822 isn't related to calcined clay. It's DE, which is silica formed by dead algae.

    Are you using OIl-Dry, which is made of calcined clay? Only 8822 is made of DE.

    Thanks for the video!

  4. Hi Ben, I take my time to watch the video 2 to 3 times before comment, the work is excellent and very informative, thougth I had to write down all data to understand and compare.

    I think is a little confusing, you mention two ranks, the first one is for density of material, wich is not relevant to even make a rank, and might confuse with the water retention that is the main thing.
    Maybe in the end would have been good to have a chart or something.
    The most important is that I want to say thank you, I have all data and studied them a lot !
    For future maybe you could make one of CIC with TDS measuring. Thanks again for sharing this, you are awesome

  5. A detailed list of this information is available in the video description, along with corrections and notes. Big shout-outs and thanks to @prana2000, @Nacho_Nacho, @AdornThyHeadset, @GUSTAVO_TORRES & my wife Julie for pointing out needed areas of future improvements! Keep those critiques coming – how else do we learn?! Love to you all!

  6. I always appreciate a scientific approach to bonsai, especially on the complex topic of soils. maybe your experiments will spare me from having to test the same things.

  7. Thank you ! I love tests like these and your glass selection was good. If possible, try out crushed brick pieces too. I believe in america, you can buy it from some garden shops, else crush enough for the test. i liked the rankings given in the description and your video could have been organized like a countdown – say, from 10 to 1 and show the full rankings at the end of the video. But you are now aware of it, judging by the comments. Good work ! Looking forward to the remaining parts. Will it be about drainage and aeration ? It would be great if you can touch upon the benefits / drawbacks of self watering bonsai and the role of substrate from that perspective. You have inspired me to finish my own documentary on pot design, which went into hibernation due to writers block, a general disinterest from my attention demanding plants and some life distractions. Restarting tonight. Script is half done.

  8. This is excellent content to help me decide on what to go with for a base bonsai mix. It seems like everyone has their own opinions, but it's great to see some actual facts based comparisons. I can't wait to see the other tests you do!

  9. I have been following you for several months now. Thank you
    for a very informative and clear analysis of water retention in bonsai soils. I
    have one doubt I would like for you to check, on you percentage calculation for
    pine bark. I ran you numbers and I get 33.3%, loss not 14.8. Thanks again.

  10. That was the most precise approach to this kind of video that I have seen on Youtube. Congratulations. That was very well done. Eagerly waiting for the next one.
    P.s: What the fuck was that black magic boiling water in the end of the video? xD

  11. Is it bad to use pea pebbles as the bulk part of ur soil? im from ohio and cant seem to find alot of this stuff.

  12. This video is what I've been waiting for so long just wanted to know how it goes..I'm excited to try it …cant wait to see some updates of your tees …

  13. Привет! Подскажи пожалуйста какой грунт ты используешь, что это за мелкие камни???У нас в России очень мало информации по субстрам. Везде пишут что надо использовать землю , там где выкопал растение, у меня ямадори растут с той землей с которой выкопал

  14. I don't mean this as an insult in any way but sometimes the way you speak makes you sound a bit robotic, it's not a bad thing or anything i just like to imagine that you are an android sent back from the future who loves trees and decided to make bonsai videos to share with the world instead of attempting to wipe out humanity and now your android overlords are super pissed because they found your YouTube channel in the future 😀

    again i mean no offence 😀 i really like your videos, i find Bonsai fascinating, just not brave enough to try it myself yet.

  15. I already congratulated you for the tests. You had a brilliant idea. I now have a few questions regarding your protocol: What was the volume of each component? Why soaking the substrate for an hour? Would a minute or two be more representative of a normal big watering? Why have you chosen 105 minutes for the first weighting and 315 minutes for the second?
    I am asking you those question because I want to run similar tests using also chabazite so I can compare it with the other components (perlite, diatomaceous earth, kanuma, Turface MVP and expanded shale . I will try to measure the water loss every 15 minutes for 4 hours so I can draw charts. I will be more than happy to share the results.
    Best, Pierre

  16. Very, very good even this test, very good video, I think that little by little is helping me to identify which will be the best substrate, better percentage of the mixture for the plant, more drainage or not, I think I'll give a suggestion of test ok?

  17. Awesome stuff buddy. I'm from the Appalachians as well here in pa. Not sure where your from in the A mountains. This help a great deal either way

  18. You have one of the best Bonsai channels, I love your style. I am currently binge watching all your Yamadori videos, I cant get enough.

  19. great video. I don't grow bonsias but the test is great and very helpful. I grow orchids in inorganic media. Glad I found your channel ♥

  20. Hey congrats for your videos. Great job. Can you please tell me what kind of soil mix do you use for your trees? Thnks a lot i would apreciate that. Congrats from Portugal.

  21. Really great vid. I am trying to get into Bonsai… I have been collecting some specimens to this end. I have a 7 year plus lemon tree, an osage orange sprout, avocado, some kind of pine, a mexican poppy and a mulberry… so far, my ginko seeds have failed. I have collected some pots and other materials for making soil. I am doing everything with found materials, or thrift store flotsam. I haven't yet taken anything out of its regular soil… I want to make my soil from the get-go. I am thinking of using broken brick, pottery, lava rock, maybe broken-up limestone chips, I have some ash with borer rot that I want to try to use… maybe charcoal… and I have been trying to think of ways of turning cow manure into rock form… maybe through boiling with baking soda and firing it without air. I would also like to dig up local clay and fire that as well.

    I imagine there are several factors I will have to take into consideration… water retention, nutrient source, weight and ph. I imagine Mulberry to be a great primer in my experiments as it is hardy and proliferate… also, the osage orange, I believe is hardy as well, and the most rot resistant wood in North America. But the Osage Orange specimen I have sprouted out of some steps I put into a hugelkulture pumpkin patch bed that I made for a neighbor… it has a great form and strong sentimental value… so I am hesitant to experiment with it.

    Also, I keep red wrigglers and Bokashi compost… so I will amend my water with these.

    Oh, and I want to make standard in my plantings the use of moss… which I have obtained an aquarium to begin cultivating.

    Any advice anyone might have to offer would be greatly appreciated. Again, thanks for the great video. I have subscribed to your channel and given a thumbs-up to … "praise the good…"

  22. Very helpful video indeed, thanks!
    Just wonder if it is a mistake about pelite vs sand. It says they retain 14g and 12g of water respectively, quite similar, but the loss is about twice larger for sand – how can it be?!

  23. Well YOU probably sick of hearing this but I agree the best vid I have seen Very informative. I have subscribed to your channel. I look forward seeing other vid. Bob, Ontario, canada

  24. A while ago, I heard on the internet that over time, Turface can become hydrophobic, and leave dry areas under the surface. Anyone know if there is any truth to that, or if it is of real concern? Just curious what experiences others have had with Turface. Let it be known that I use Turface myself. Great video, and thanks for any information.

  25. Good job! Interesting video, but the water retention is influenced by the microporosity and the macroporosity of the substrates therefore by their granulometry. it would be interesting to see a comparison between some inorganic substrates with the same average particle size

  26. What stops us from using straight up crushed bricks for growing bonsais? They have porous structure, they drain well too. Mixed with some soft organic soil it would do good for water retention too.

  27. Very nice video and presentation. One small note I'd like to address though is that, while they are markedly similar, calcined clay (which looks like what you used in this video) and diatomaceous earth are not the same thing, even though they have very similar properties. diatomaceous earth generally does not break down as easily as calcined clay (turface is also a type of calcined clay) and is made of fossils of diatoms (which gives it the name) two common sources of these are the napa and advanced autoparts oil absorption products, one uses diatomaceousmearth, the other is calcined clay.

  28. A very good video for comparing different types of Bonsai planting material. I am impressed that Bonsai are grown all over the world. I have to admit that I do not have any Bonsai plants even thought there are many Bonsai nurseries near my home. I am thinking about buying some small Bonsai.

  29. Great video, but I will give some constructive feedback. It would have been immensely helpful to see a summary table or graph at the end. Thanks!

  30. Awesome video! One note, when you talked about the peat moss, you mentioned sphagnum moss. Not the same thing 🙂

  31. question… i have a ten years ond olive bonsai. do u think i need some special soil? right now i have only good black ground.

  32. I keep referring back to this video again and again and thought about it a lot when sourcing materials for repotting some orchids recently! Fantastic experiment… I bought Turface to try it, I usually use Seachem Flourite which is a very very very close product. A lot of my orchids are potted purely in Seachem Flourite and are thriving. Not all can be potted purely in it, though, so some have fir bark, lava rock, charcoal, sphagnum moss, and perlite mixed in as well. Thank you for this resource!

  33. I get small bags of long stand sphagnum moss (not the brown peat stuff) at homedepot, all though, out the 2 closest to me, only the one in the nicer area carries it. It's usually next to the orchid stuff, which is usually by the plant propagation stuff, which is usually by indoor plants..lol
    Please test some! i NEED to know if it's better then coco!

  34. I had no idea diatomaceous earth came in granules like that, I've always used the powder as an organic "pesticide" (and in the pool) i wonder if those granules kill bugs?

  35. I guess for succulent and cacti use, the less water retention the better. Please correct me if I am wrong. Thanks for the great video.

  36. Here in Brazil we bonsaists use much the Caqueira, which is basically pieces of broken clay tile, has excellent drainage and aeration. https://images.app.goo.gl/fRRTT8RtwJpTu3738

  37. You did a video about three years ago about transforming a dogwood tree into a bonsai. Can you tell me what were the soil components you used? It looked very rocky as if it had Acadama, and some type of gravel or chips. I am going out to find a Wisteria plant to turn into a bonsai and hopefully can find one about the same size as your dogwood.

  38. Thanks. Good job we have people like this because I would never have the patience. I would buy mine from a dealer who does all this kind of stuff for me, but I really find it interesting to listen to. Keep it up.

  39. Sorry Im late … Im danish. Thanks for a very good video. Maybe I have lost something, but ….. I think its only show which material pic up most H2O and keep it. From my point of view it is more importent to show, which material easyly pics H2O, fertilasors and O2 up AND are willing to give it to the rots. Otherwise it will be a competion between soil and rots. I can have missed something?

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