4 X 12? Seriously? About all you're gonna get is a few tomato plants (or in your case, a few bell pepper plants.)
Scoobs and I dug up a 12 X 20 foot patch last year and I want to do more, but trying to figure out which way to go is going to be interesting.
I do my herbs in a couple of planters I leave on the railing of the back porch (basil, cilantro, parsley, chives, oregano, and tarragon or dill.)
As far as the garden itself goes this year, it's for sure gonna be corn, green beans, carrots (if the damn squirrels don't eat them), squash, at least 2-3 types of tomatoes, pumpkin, and cantalopes. No way we're going to do quite as many zuchinni, and not doing radishes at all.
That's on top of the regular stuff like apples, cherries, blueberries, raspberries (probably have to replace those bushes this year), strawberries, and peaches. Hmmmm...plum trees, anyone?