By L_plates
North Yorkshire,
United Kingdom 
I am building a long rectangular wooden planter with a trellis back to be sited on top of a wall. The wood has been preserved. Do I need to line the box with something like pond liner and/or do I need to drill drainage holes in the bottom of the planter. It is approx 18" high x 12" deep and 9' long.
1 Jul, 2010
Answers
welcome to Goy L plates. I agree with busy bee. How high is the wall on which you are planningto site it. It could probably do with being lifted on feet like you would do with a pot to allow water to drain.
1 Jul, 2010
I would suggest instead of lining it with plastic you find a plastic container that fits it much easier to manage as you can cover the drainage hole so they dont clog and the roots wont puncture.
2 Jul, 2010
Good thinking Drc726. That will also allow excess water to drain off.
2 Jul, 2010
I highly recommend lining the box, just to prevent the wood rotting so it stays looking nice. Yes I would also drill drainage holes, I have on my planters so they don't stay bogged with water.
Love the name btw :o)
And welcome to GOY
1 Jul, 2010