Molly, you should be able to direct sow the lettuce and spinach mustard in the ground. I have already WS'd salvias this year and last year I WS'd poppies and they're doing great so far. Didn't bloom last year, but they've made it through the winter and are still nice and green and plump, so I'm waiting for huge blooms this year. As Karen has already said, you can direct sow those poppies, too. The pepper plants I'd wait a while on.
