I want to make a barrel shaped planter, with 12 straight sides out of 4 by 1 inch timber. The height of the planter is obviously variable depending on the length the 4 by 1's are cut.

I can mitre the edges, but my problem is what is the best way to join them? Bearing in mind the pressure will be from inside to out, thus always trying to force the joints apart. I do not want to put any banding round the planter and wondered if anyone can suggest a better alternative to biscuit joints.

Oldun