Really no such thing as too late for peas up here. I planted mine last week. Two years ago I planted a spring crop, and when they were done, planted another crop in the middle of summer and they grew just fine. You are a zone warmer, but go ahead and plant.

I'm interested in growing peas too ... what is the minimum depth of soil/size of container you recommend? Thanks ...

Depends on how many peas you want to grow. Last winter we planted a few in a tiny pot and put it on the window sill and grew them just for the fun of it. Even got a few peas out of it. They'll grow in just about anywhere, in anything, in as little as a few inches of soil. Just plant them in whatever you have and allow an inch or two between plants.