Grab a cheap bag of lentils or chickpeas. When the summer plants check out (I note we have a frost advisory tonight, so it may be soon), clear the bed and sow it thickly with the legumes. Rake them in a bit or cover it with screen to save the seed from the birds. They'll grow over the winter, start taking off in spring, and they'll be nice and lush around about the time you'd plant tomatoes and peppers. Turn them under, let the bed sit for a few days, and plant. They'll give you a gentle nitrogen boost and good organic matter, and they don't tie up the bed too long.