corrugated metal roofing raised bed question

We have a terrible problem with gophers around here so once we're done with the landscape renewal to our back yard I'm thinking of building a couple 4 X 8 above ground garden boxes (the added height will also make my back happy). I'm thinking of making the sides from corrugated metal roofing material - with the appropriate wood framing & supports. I'm just wondering though - should I drill any holes in the bottom sheets of roofing for drainage? I guess the panels won't be assembled in a water tight way so maybe it wouldn't matter.

Anybody made these before? If so, any tips?
Thanks!

 

Paint them white as the sun will heat them up...and the soil close to the sides ....and affect roots.