I want to build raised flower beds with used bricks -- mostly sandstone 4"
depth and various heights from 2" to 8". Any experienced people want to
comment? Want to know if this is a bad idea or what problems might come up
and how to avoid them. Assume I am cleaning off the old mortar as well as I
can.

Can a 2-foot wall that is 4" wide and 9 feet long hold or do I need to build
in supports? I'm thinking of doubling up the brick at key points along each
of the main walls of the flower beds (dimensions: 9' x 28").

Thanks,

Kevin