when to transplant plugs
I have plugs to transplant, some 128, some 36 per tray, and am wondering when I can transplant them. I have mostly perennials now-achillea and scabiosa, but expect to receive annuals next week, all the 128 size. I've been keeping them in a 60 degree shop at night, and putting them outside for a couple hours, slowly building, each day? We're on the border of zone 4/5, and have had nights between 34 and 38 degrees this week, but the forecast looks like we'll be in the upper 30's and 40's by next week. Our last frost date, traditionally, is May 10th. Do I need to put them outside more? Lower the nighttime temp in the shop? Let them grow a bit more?
I know there is a lot of questions there--sorry about that. I have only grown plants from seed so far, directly seeded outside, as well as much bigger perennial transplants, so I'm nervous about making mistakes! Not that I can't garden and make mistakes--it goes with the territory. But as the saying goes--no mistakes, only happy accidents.
Thanks for any input. I've enjoyed reading this forum for a long time.