Peppers. Tomatoes in March? Because it's cold out I want to think hot. Growing peppers and tomatoes in the Portland area is certainly possible though not ideal. Why? Our cool nights. I've mainly grown hot peppers and a few varieties of sweet peppers in containers so that the soil stays a little warmer than it does in the ground. You can also move them as you chase the sun in August and September. I've had a lot of success with tomatoes even with as little as seven hours of sun. They weren't the most productive but they were tasty and better than a slap on the forehead.
I run into a problem of aesthetics when growing vegetables and using growth aids like wall o water and plastic mulch tarps. I know wall o water works but I just don't want to look at a plastic tomato plant in my garden. I'm willing to settle for less yield and a shorter growing season because I am so vain. Would you rather be ugly and live to a hundred or beautiful and live to 80?
Okay, you don't have to answer that question. But answer these. Are you a canner? Do you want a truck-load of salsa that you can eat all winter? Than use wall o water. You'll get more yield. Do you enjoy the beauty of a tomato or pepper plant but don't need a mess of fruit that might just go to waste? Then garden naked, the old-fashioned way.