When a Pot is More than Just a Pot!

To pretty much every person imaginable, a pot is just a pot. To me, this pot is possibilities! Having maxed out my 100 square feet of gardening space, I'd still like to be able to grow some leafy greens or carrots. I can put it at the edge of my plot and grow something more suitable to a container. At first I was thinking of growing carrots, but I'm not sure this pot is big enough. I think I'll try Swiss Chard since we both like eating it, it doesn't require deep roots and it is more tolerant to heat than a lot of lettuces (or so I've read). Although I am tempted to grow some Bibb lettuce, I think it might be a lite too late. I suspect warm summer temperatures are right around the corner (or so i hope), but I would like to try growing something new, especially greens because I haven't had much luck in the past. In fact, I've had almost no luck. One head of lettuce worked in 2012 and this year, none! I'm not sure if that was because I started them with the heat-loving seeds on the warm seed-starting mat or what, but none looked strong-maybe lettuce just comes up more delicately than tomatoes and eggplant-I'm not sure. That'll be an experiment for next winter/early spring.