Posted on 6 Comments

BonsaiBlock, a replacement for Turface

Originally posted 4-20-2016

Bonsai Block is a superior replacement for turface. BonsaiBlock advantages include…

  • A constant ¼ inch size versus turface, which is made up of smaller particles
    that reduce drainage.
  • Less water retention. Our tests show a 20 percent water retention rate for
    Bonsai Block versus Turface that shows a retention rate of 44 percent. This
    can reduce root rot. Please see our blog at for more
    information on these tests.
  • Better cosmetics. BonsaiBlock looks better in shape and color. It has a natural
    pebble look with multiple earth tones. Unlike Turface that has a light
    color machined appearance.
  • High firing temperatures. Both Turface and BonsaiBlock are calcined clay but
    BonsaiBlock is fired at higher temps making a stronger material that will
    not break down as fast.
  • BonsaiBlock has a consistent PH range. Our tests have shown Turface with an acidic PH
    of 4.41 versus BonsaiBlock with a PH of 8.63. Turface labels show a very
    wide PH range of 4.0 to 8.0. This is very inconsistent in my opinion.

BonsaiBlock is a superior product and is priced lower than lava and about the same as Turface. It has many of the same properties of Maroon Lava and superior properties to Turface.

Bonsai artists will continue to use turface as a soil ingredient and that is your decision. We sell both kinds. We can only provide information for
alternative products to consider. It is my opinion that turface should only be used for acid loving shohin or mame trees.

We are using a mix of two parts BonsaiBlock, two parts pumice and one part pine bark fines for tropicals.

Thanks for the continued support.

By Bonsai Jack

6 thoughts on “BonsaiBlock, a replacement for Turface

  1. When you are comparing the water retention (and acidity) of Turface and Bonsai Block in your studies, are you comparing equal sizes (1/4th inch turface compared to 1/4 inch bonsai block). Or are you comparing Bonsai Block to unscreened turface which includes much smaller particles and therefore has higher water retention?

    1. Thanks for the reply. 1/4 inch Turface did not exist in 2014 and could not be tested. A bag of Turface MVP for example does not contain a single 1/4 inch particle.
      Montmorillonite clay is naturally acidic, no matter the particle size. Monto Clay(1/4 inch Turface) for example has a pH of 5.6. This is not a bad thing as it helps balance out other ingredients in a soil mix. The biggest issue with regular Turface is the particle size. Smaller particles will settle to the bottom of the pot when mixed with other 1/4 inch particles. This can cause drainage issues, compaction and acidic shock to the root system.
      I hope this helps


  2. I’m looking at replacing my use of Turface with a use of Bonsai Block. With Turface, the standard readily available MVP small partial size, the product would stay moist, but not soggy, below the surface for most of the day. Drained well. This was good in my opinion. Will Bonsai Block respond similarly and hold some water below the top surface?…..and release it throughout the day or evening before the next watering. My trees are in wooden boxes, sides of basic treated 1×6 with wooden slat bottoms that drain very well, if that matters.

    1. Hello John,
      I think you will have different results because of the particle size and hardness. If the Turface MVP is working for you it’s not a good idea to change it. They also vary in pH and hardness. They are both clay products but one is montmorillonite(acidifier) and the other is standard ball clay(slightly alkaline). It’s like comparing peat moss to ¼ inch sand. They are both great products but perform different tasks. You may be more interested in our Monto Clay product. It’s the exact same thing as Turface MVP but the particle size is ¼ inch.

      The best this to do is test new substrates before you rely on them.

      I hope this helps


      1. hi,
        What is bonsai block? is it the same as the DE (diatomaceous earth) soil?

        1. Thanks for the message. Bonsai Block is a fired ball clay. Similar to Akadama but fired at 2000 degrees. Have a great week. Please call or email if you have questions or concerns.

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