Most articles I read about square foot gardening involve building a raised bed over the soil in your yard. However, the neighborhood I live in does not allow for in-ground crops to be grown and they include raised beds without a bottom as being in-ground. So I am forced to add bottoms to my boxes. So far the planter boxes I am building are about 36" long, 24" wide and 15" deep. These have worked well enough for carrots, snap peas and a raspberry bush (though the raspberry bush quickly took over and out-grew its box. I had bigger boxes, but, as I have a bad back, they weren't very easy to move. Even these smaller ones tend to be fairly uncomfortable to move with my wife's help (I'm thinking of adding casters). But I have been curious as to just what depth I could get away with for most vegetables?
Thank you in advance for your input.