[quote=Popcorn Lover]I'm interested in building some inexpensive planters for our driveway.
I want them to be about 12' long, 2' wide and 2' tall, with open
bottoms for drainage.

I thought of making them with 8x8x16 concrete blocks which are a whole
lot less expensive but they'd be pretty ugly that way, wouldn't they?

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- Popcorn Lover
QUOTE]
Concrete can be painted to make it more attractive. It's worth remembering that it's a very alkaline material and consequently would raise the pH of the soil in the planter (this would be a problem if you were hoping to grow lime-hating plants). Could you maybe use treated timber, lining the inside of the planter with thick polythene to prevent the wood coming into contact with the compost? I know they wouldn't last forever.