expanded shale for clay soil

[Jane Yeoman]

Has anyone used expanded sale to improve clay soil? I read of a study by Texas A&M which indicated it is a permanent solution to improving the air and drainage properties for gardening.

Has anyone used it?

[Billy]

No I haven't, but I have serious doubts about it being the single answer to your soil's problems. As part of a strategy, it seems like a good idea.

If you have tight compacted clay and caliche soil, you should add a mix of organic matter with one of the newer inorganic amendments. I recommend adding an inorganic amendment for heavy clay soil, such as Turface® (calcined clay), Tru-Grow® (expanded blue shale), Ecolite (zeolite) or Axis® (diatomaceous earth) and Profile for sandy soil. Expanded blue shale is also available from Soil Mender and is called natural expanded shale. These are a few of the better inorganic amendments that retain water and nutrients, in addition to creating more spaces for air and water. Other inorganic amendments with much more limited ability to retain water and nutrients are crushed granite, granite and lava sand, greensand, glass sand, and finally, regular sand. If your clay soil develops cracks during summer droughts, please consider adding the inorganic as well as organic amendments.

[Gunner]

Jane, I use a variety of coarse aggregates from my hydroponics and bonsai to work into my clay soil. The rough and pitted surface area is the key. Properly sized, it really does work well in getting a good soil structure where water and air can flow and roots can grow. I do not recommend sand, even the highly touted coarse builders sand especially using coarse aggregate I cant plug up many of the channels you just created. I'm sure you understand the concept, if not do a quick read on bonsai soils.

I wouldn't hunt the Tru-Grow brand down if it is not locally available. No cost benefit in shipping a bunch of rock. As for other value options, price out chicken grit ( I use a #2), Diatomaceous Earth (DE) or kitty litter,( hopefully not used or perfumed). small river or tumbled rock. You have to be careful with some crushed rocks such as granite because the sharp edges can cut into roots . You can get DE fairly cheap at the NAPA auto parts store. It is sold as super- sorb or some such,it is a floor sweep for spills. Do wash( a couple of times even) and drain off the liquid and save if you want a really good insecticide( much better than tobacco) . Just ensure you put a Warning label on it! It kinda looks like milk. ;]

[Nad R]

My evil plan is working, nice to see that you have been conforming and indoctrinated gunner :)