Annette Guttierez made a cheap and simple but elegant planter for a patio using cinder blocks. Here's how she did it:
The wall was built with 12" cinder blocks (the kind you would use to build a column) and we used Liquid nails to hold them together because I didn't want grout lines and also it gave us more flexibility. In fact in order to make bottoms for the blocks that are sticking forward, we cut pieces of cinder block to fit the inside and then liquid nailed them in. We love liquid nails.
Link ~via Dude Craft | Photo: Potted