I'm researching expanded shale as a substrate for ebb & flow bed. Ebay has someone in Texas selling 100lbs for over $100 (incl. shipping). And http://www.utelite.com/products.html in Utah. I've emailed them for an estimate. Is anyone in the PNW using/selling expanded shale?
Hang in there then Ian.
Rob Torcellini uses expanded shale in his raft net pots. He wets it down before filling the net pots so that then he adds the seed it will stick instead of falling through. His rafts are not very thick so the shale probably wicks enough mosisture to germinate things like lettuce right on the surface.
Ah! My ears are burning! I'm having very good luck with the shale in the net pots. My shale is 3/4", but I ran some through a 1/2" screen so the pieces in the pots are a bit smaller. This seems to work even better than using 3/4" After I screen the 1/2". I screened it again through a 3/8" to get rid of the really small stuff since I didn't want it to fall out of the pots at all.
I just keep a 5 gallon bucket about 1/2 full with media and scoop the shale right into the pots....when I'm done with it, just dump it shale back in the bucket. It's nice since I don't have to by the rock wool plugs and it's 100% recycled.
I think it was mentioned earlier, but you should wash your shale. I usually fill my wheelbarrow with water and dump a bunch in, shovel it out on to a screen and rinse the rest off. It's not too bad.
here's a video that shows the net pots: http://youtu.be/xKZhqnGJ1a8
Hi Rob, finally got a high speed connection and was able to watch your video. Great Stuff!