the frost warnings are almost at a close.I always have been particular about certain plants i know should not be outside because of frost warnings,like geraniums and basil.but for the most part,i believed that the cool weather actually gives the roots a golden opportunity to build and strengthen,which will provide you with stronger ,healthier plants.just water deeply in the morning because evening waterings can propagate fungus,even this early in the season.memorial day is the perfect target date for your zone though.but if their are frost warnings,throw an old sheet or tarp over the plants for the night and you should be just fine!