2 Dry Quarts 1/4 Inch Monto Clay pH 5.6 (Montmorillonite Calcined Clay) Bonsai Soil Amendment


Monto Clay ®, short for Montmorillonite clay, is a fired clay product used to amend soil. Montmorillonite is sold under other brand names such as Turface MVP®.

The advantage of Monto Clay is the 1/4 inch particle size. 1/4 inch particles prevent dry spots, poor drainage and settling which can create acidic shock. Ideal for use in bonsai soil, cactus soil, succulent soil, hydroponics and amending soil to increase drainage.

Montmorillonite is known for its cation exchange capacity(CEC). It's also a great acidifier. The acidic properties help offset the alkaline properties of other ingredients such as pumice and lava rock. Monto clay is a great substitute for Akadama.

Condition: Screened, Tumbled, Dried and Bagged.

  • Similar properties of hard Akadama.
  • Uniform 1/4 inch Particle size prevents dry spots, poor drainage and settling.
  • Acidifying soil amendment
  • Pathogen free high fired clay
  • Available in 2 Quart, 1 Gallon, 2 Gallon, 3.5 Gallon, 7 Gallon, 14 Gallon and 28 Gallon SKUs


Monto Clay® comes from the same company, mine and processing plant as Turface®. It's the exact same product, only larger. Although this is technically 1/4 inch Turface we are not permitted to sell it as Turface®. This is because it conflicts with the Turface brand name. The folks at Profile products were kind enough to manufacture this product to our specifications. This product is exclusive to the Bonsai Jack product line.


Did you know?
All of our soil products are state inspected and tested on a regular basis in order to comply with multi-state regulations.
This ensures you receive material free of dangerous pathogens that can damage or kill plants. This is also required to maintain six nursery stamps that allow us to ship to all 50 states.

Click the Additional Information tab for more details.


SKU: 799600831106 Categories: ,

Additional information

Weight3 lbs
Dimensions6 × 8 × 4 in

Light Brown / Khaki Tan. Similar to Turface MVP

Raw Material

Calcined Montmorillonite Clay

Country of Origin(COO)

United States

Average Particle Size

1/4 Inch

Minimum Particle Size

1/8th Inch

Maximum Particle Size

3/8ths Inch


Profile Products


2, Dry

Cubic Inches


Cubic Feet



2 Quart Bag



Plant Type

Cactus / cacti, succulent, orchid, fruiting, flowering and citrus.


No dyes or chemicals.

Other Applications

Fast draining soil blends that require an acidic additive.

Bulk Density

.332 ounces per cubic inch


  1. enchantedpoodles

    Hello – I want to add either Monto clay or Bonsai Block to a peat moss soil for tropical plants (not succulents or cacti) to increase the drainage. Do you have an opinion about which would be best for that? Thank you.

    • Bonsai Jack

      Hello Dori. Thanks for the message. Both of them are calcined clay and will work fine. Monto Clay is an acidifier and Bonsai Block is slightly alkaline. If you are unsure of which one you need it would be a good idea to stick with the Monto Clay. Talk soon Thanks Jack

  2. Lety

    Is this product similar to seramis?

    • Lety

      Hello Jack,

      Thanks for the reply. I am currently using Seramis but can only get the smaller size in the US. (Which is fine for smaller rooted orchids)
      I was also confused with their statement about being ph neutral……………..IT IS NOT! I can send you a sample if you like for testing. I’ve been able to lower the ph by boiling the sermais, letting it sit in water over night and rinsing with clean water before using.

      • Bonsai Jack

        That’s good information. You are correct. Seramis and Moto Clay are acidifiers. That is a good thing though as it offsets the alkalinity of other ingredients without the need of organic acidifiers such as pine and fir bark. No samples needed thanks though. We are pretty booked up on the product line until 2019. Have a great weekend.

    • Bonsai Jack

      Hello Lety. I wish I had a clear answer for you but I have not seen Seramis in person before.

      I did some research on Seramis and came across this photo http://www.germandeli.com/product-images/Seramis-Ton-Granulat-7-5_main-3.jpg?fcts=20170701044940
      Seramis and Monto Clay appear to be the same product type

      The product looks very similar to Monto Clay. It appears to be the same thing according to this statement “Seramis is “calcined montmorillonite clay”. Monto Clay is also a calcined montomorillonite clay product.
      I am confused because they mentioned Seramis is pH neutral. Which is not true if its Montmorillonite clay. pH neutral statements are common among the gardening industry when the vast majority of them are untrue. Montmorillonite is an acidic clay product.

      I would be interested in hearing your feedback if you have some Seramis to compare with Monto Clay. We will also be happy to lab test, at not charge, any Seramis samples you send our way for comparison.
      Seramis is not available in the USA. I checked the USTPO to see if the name has been trademarked. It was originally trademarked by SERAMIS GMBH from Germany and it is now owned by Mars, Inc, the same guys that make candy bars. They may have an interest in marketing the product in the USA or could be holding it as an asset.

      I hope this helps. Please be sure to try it before relying on it.


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