I have quit wrapping the coldframe at night, just closing it tight (it needs new weather stripping already). I had been regularly bringing tomato seedlings indoors at night, and leaving coleus out in the coldframe. They are dropping a few lower leaves but otherwise seem fine. Reading a book called Garden Secrets, and the part about temperature influence on plants tells me that tomatoes actually will flower sooner if they experience cool nights (between 43-55°) while young plants. Then I looked up cold hardiness for some of my other plants- particularly the perennials, and found that while my coleus will certainly survive the low forties, it can harm the overall health of the plant so they're not as lush later on. Those plants shouldn't be out until it's at least 60° overnight! So I switched my habit. I'm now putting tomatoes in a tray on the deck during the day, to get the most sun, and then putting them in the coldframe house at night. And bringing the coleus inside.
It looks like it's regularly going to be above 42° at night now, so I've planted out my sunpatiens. These are like impatiens, but more drought-hardy and can tolerate full sun. They were kind of an impulse buy.
I put one out by the mailbox, and the other by my front porch. The plant is supposed to get up to 36" across!
Right now they are rather small, and risk being stomped on by kids who are used to jumping off the porch onto what was a blank area. I've warned them to please not walk through the perennial bed, or step in this area I'm trying to plant, and they usually listen but sometimes forget.