Saturday, February 6, 2021

Sources of Expanded Shale and such


There has been discussion among rock gardeners, roof gardeners, bonsai growers, and the crevice people about sourcing expanded shale and other permeable aggregates. These materials are like porous gravel, holding water and nutrients without organic material- which is very useful mixed into crevice garden soil media and in containers to grow alpine or rock plants.

Here is a list I've been compiling:

Haydite (Ohio) 

Seramis (Germany/Europe/UK)

Permatill (by Stalite) North Carolina

Turface (actually calcined clay) or “Pro’sChoice” brand

Trinity Expanded Shale (Golden, Colorado)

Utelite  (Utah)

Soil Mender brand Expanded Shale (Texas)

Cat litter/“Oil-Dri”- coming in bags at the pet or automotive store, these occasionally turn out to be useful expanded shale, calcined clay, or diatomaceous earth, but most of the time are just clay clods- adding water will quickly reveal the truth. A source for desperate times. 

Broken pots- Terra-cotta, porous pots have the absorbent qualities of all the above, but this is not true for vitrified stoneware pots which are fired hotted and not porous. Broken terra-cotta may have been used for a very long time historically by rock gardeners in-the-know! Not a bad plan-B if nothing else is available or you want to dispose of old pots.


Panayoti Kelaidis said...

You didn't mention Arcosa Lightweight ( which has national distribution, including the TXI plant just south of Boulder. This is most commonly utilized in Denver--and was the medium of preference for many Carnation growers during the floral greenhouse boom in Colorado from the 1950's that fizzled in the 1980's.

Joe Wittig said...

It looks like expanded shale can be purchased for $72 per cubic yard from
1541 Boston Ave, Longmont, CO 80501
303.682.2314 PH

Arcosa doesn't sell smaller quantities than dump trucks and train cars.

This was the only retail location I could find that would sell by the cubic yard.

Unknown said...

Thanks Kenton & Joe! We need to source expanded shale for a crevice garden for public garden in Greeley this source will work GREAT!

I am also reaching out to our local Clay Center to recycle some broken pots too.