Wood probably retains some heat but not like brick. Purchase a few Wall of Water if you're worried about night temperatures early in the season. Covering the fence with something white would reflect a lot of light. I plant next to a white fence and it has been very beneficial. It also blocks a cold north wind off of Lake Erie.
Jennifer

With that wall where it is, you could simply staple a sheet of clear plastic midway up the fence and bring it down to a foot or two in front of the plants and cinch it to the ground with wood or whatever you have lying around. Coupled with the heat absorption of what I assume is the fairly dark wood background of the fence, you'll have your own little greenhouse for just a couple bucks worth of heavy plastic.

Hmm, now we're talking. I'll have to give that plastic tent idea a try. Maybe together with a black background and WoW at the same time. And then maybe I can switch over to white when it heats up outside. :)

Good ideas. Here's one to consider. In the summer, use silvered plastic or mylar to line the fence. It will reflect TONS of light and possibly increase your harvest. Not only that, it will help prevent the wood from retaining heat. I go through several mylar campers' emergency blankets every spring/summer. They're fairly cheap and they work wonders. Good for mulch, too.