I'm on the line b/t zones 4 & 5, so pretty similar to where you are. Like I said in another post, we usually get cold weather all through May w/ a few frosts here & there. I'll likely be planting my peppers, toms, beans, squash, cukes & corn (1st time

) the first week of June. That's when all those plants, except the toms, went in last year, and they had plenty of time to develop. My toms went in on May 20th, but they weren't happy about it

They didn't take off until June.
So far, I have lettuce, radish, spinach, peas, brocolli, brussels sprouts, beets, swiss chard, carrots, & potatoes in the ground.