Kathy,
It all depends of how protected your plants are, but I have started planting some a week ago (Bachelor's buttons, malvas, calendulas among them). I even transplanted lettuce as soon as they came up-a month ago?. They are all doing well. Penny even did her Morning glories! Last night's frost did not damage anything. Of course, again, it all depends of the type of plants and the protection--what I have transplanted thus far, is among tulips--which does give much protection. I am always more concerned about 'heavy rain' than I am of a reasonable frost.

I am about to do much more now.

I believe Rochester is in zone 6. If you type your zip code in the Park's site, you should get your zone.

Good luck,
Anne-Marie, from zone 5.

Thank you, Anne Marie. I'm not ready to plant out yet, but still worried about taking the covers off completely...

Yes, your map link shows me in zone 6.

YES.. do take your covers OFF, Kathy, especially if your containers are wet, as mine were after the snow melted.. a long time ago. You can always put them back if necessary. We have so many SQUIRRELS in our backyard getting into everything that mine are covered with a grid.
Good luck
Anne-Marie

Thank you!

I planted my winter sown stuff already, after all, they've been hardening off all along. I did lose some plants, not from frost, but heat. We had some unseasonably hot weather, and the plants I still had covered, in containers got a little fried from the heat.