expanded shale

[josepi.13]

anyone ever use expanded shale in their mix or for semi hydro? i seen some sold by sunleaves. let me know what you guys think

[Ray]

The bottom line is this:

ANY inert medium will work as a semi-hydroponic medium. However, each has its own set of properties when it comes to absorption, release, mineral buildup, capillarity, packing density and airiness - and whether it works depends upon the conditions in your specific growing environment.

Many years ago I tested an expanded shale product called "Stalite", which is sold for loosening up compact clay soils, and found it to absorb only about 50% of what several brands of LECA did, and due to it's non-spherical shape, its open volume was 10-20% less than theirs.

As wicking is related to absorption, if you grow in a dry environment, that's not a positive direction, but if you're in a very humid environment, it might not be an issue.

[1joyceh]

I have a couple of plants in 'rocks' an oncidium noid and a phal...have been in for around 6 months....both are doing well....no worries about overwatering

[otis 226]

I too like to use what I call 'rubble' when I can produce it. (Mostly from broken crocks, clay flower pots, ect). I may add a bit of charcoal, but with my heavy watering hand It works better for me than most other potting materials. I do live in humid FL.
Cheers,
Tony

[Hummer344]

I would preferr to use a semi-porous rock or a more absorbant medium. I use small lava rock in my mixes. It has a lot of small crevises in it the capture water which the plant can feed off of.