Raised bed questions.

Raised bed questions.

This might be a ridiculous question but I haven't found a definetive answer anywhere. I'm building two raised beds in the next couple of weekends and planning to make them both 4'x8' (I really want to avoid clambering/falling into them as I'm kinda clutzy). Our soil sucks, its virgin clay. As in, they plowed 30' off the top of a hill and that's where they built our house. With that in mind, how high(deep?) do the beds need to be assuming we grow cukes, tomatoes, pumpkins, and peppers? I've seen sites saying anywhere from 3" to 2' is good but I'm assuming that depends on a bunch of factors. Hopefully we can get away with 8-12" but I'd rather do whatever it takes the first year and be done. :) Also, what did you build your raised beds out off? Trying to decide between my two ideals of stone/brick walls and a no screw set up with composite boards. We've had termite issues in the past so I'm trying to avoid wood.
Parakeets?

Parakeets?

A bright yellow room!

A bright yellow room!

A room of one’s own.

A room of one’s own.

is out of lurking.

is out of lurking.

Asakura – a Japanese sasanqua with large flat semi-double white flowers and upright growing habit

Asakura – a Japanese sasanqua with large flat semi-double white flowers and upright growing habit

A winter project

A winter project