How much space (depth and width) would I have need of for my sweet peas? I am planning on growing sweet peas along the wall of my...

I am planning on growing sweet peas along the wall of my house and am going to sow the seeds contained by long wooden planters - in buoyant of this what do you recommend the size of these planters to be?
Answers:    Last year, I had started sweetpeas surrounded by a plastic window box. It be about 7inches illustrious X 5inches wide and 2 1/2 foot long. By the time they were 1/2foot high-ceilinged their roots were congested('rootbound') near each other and have reached resourcefully to the bottom.It was a entwined mess and they couldn't be transplanted. So i suppose you must build a bit deeper than I did. I am trying sweetpeas again this year since they grow so well from kernel. I already have several economically on their way and planted within a garden bed with a 6' trellis trailing them. It is important to enjoy something for them to support themselves on at a very low loftiness. My trellis goes adjectives the way to ground height. Some ppl start at 1foot but that would not be good for these plants. Hope i help some. This is only my second year gardenin & I'm still simply learning.
I've never grown sweet peas within containers, but I wouldn't imagine they want much room at all. I used to grow regular peas surrounded by a window box - you could probably use something simply as small. Although if you get something bigger as you would expect you could put in some nice bedding plants too - that's up to you.
Basically, I reckon anything will do, as long as you hold on to them fed and watered : )