Soil Alternatives

Two new soil products I will be testing.

Shale from Utah and zeolite from Eastern Idaho…

The shale may affect water chemistry, so will check that first with this coarse cut…but also have to get a finer screen of it to know if it is good for the trees texture-wise. This cut could be used as coarse base layer for drainage, but not much more.


Zeolite…correct screening, minor fines

These are worth testing because they are cheap (relatively) and sourced in North America.

Anyone have experience with these, especially any known issues with using shale in terms of water pH affects or breakdown in pot?

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It all depends on the area it was collected and how much calcite is in it. Mostly the pH is around 6.3 on average

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Looking forward to your findings :grin:

I’m hoping to test zeolite this spring. We’ll have to compare results.

Where did you get your soil sieves?

I bought these in 2018…but they must have been more like $70 then. You can buy them individually too. I would maybe just get a 1/4” and 1/8” set for $50 as those are the crucial sizes for bonsai soil.

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Thanks for the link.

Hi Don,
I use a shale product as the primary in my bonsai mix due to the highly humid climate I live in, coastal South Carolina. The product is called Permatill, it’s what is called expanded shale, heated to 2200 degrees. It has a good CEC, and has done well for me the last 2 seasons. Doesn’t break down at all, down side it is a bit heavy, and the size typically is on the larger size when sifted. Hard to get enough small material if you’re doing lots of smaller trees.