I really doubt you could get anything started without warm soil. if the seeds had been started in August, the little plants would probably survive if the temperatures never went below, perhaps, 25 degrees. I don't attempt any of this but did purchase a tiny box that allows me to start many seeds in spring. I have a heating cable in the stones and must be sure it is closed in the worst of weather and opened when it might overheat. I will be reading any replies to your post with great interest. Usually, photos are too big in bytes to post here, but here is the box I have on my potting bench. I had to put it together, and I permanently attached it to the bench.

bogturtle-what type of seeds do you start in this frame and when? Also, with heat, what types of temperatures are you able to maintain? Thanks in advance! I am attempting to winter sow in a new cold frame and plan on also using it to harden off my indoor starts later this spring.

The heating cable hardly keeps the box above freezing, as the weather begins to warm in March, here. So I will not be starting anything that says, plant when soil is warmed up, as squash, or tomatoes. What with the ocean being 5 miles away, Spring is very late for me.
But I will start really frost resistant ones, that I just don't want to start right in rows in the soil. Many seeds need a frost period to germinate properly. They are cooled by the company that sells them, usually. They do fine in the box.
I start kohlrabi and swiss chard right in rows in the garden, patiently thinning, once they show up. But, because of deer and rabbits, I have backed these up with ones from the box.
Plants I don't want or need, by the dozens are started in the box.
For me, that would be easy ones like Platycodon or Digitalis (foxglove), Hollyhocks, and iffier ones like Geum, or Salvia. All my sorts of annual flowering vines are started in the box.
It just gives me a few weeks start up, as the garden takes a long time to warm up.

Thanks for the info! I's good to find out that others have had success starting hardy perennials in a cold frame. Last question....I think. How many weeks from the last frost do you start your Platycodon? I have already sowed some and am feeling a little nervous about it. I thought if the container method worked..then possibly a cold frame would act in the same way.

I would expect that even if you had planted them before Winter, out of doors, they would do fine. Just a controlled repeat of what happens, naturally. Never tried it, actually, but start them in the cold frame around March. Chiefly as I have not saved seed from plants I have, so I am using Spring purchased packets.
I have trays and trays of Butterfly Weed seed, from my plants. I plan to give the plants to local folks concerned about Monarch Butterfly decline. They have been out in the open, covered with mesh, to stop voles and mice, all Winter. Expect they will grow, but never guarantee anything. So the most I usually of the coldframe is for special, small quantities of annual seed that need to get started to bloom reasonably, before Summer is too far gone.

Thanks for the info! I am trying not to count on everything working out. In fact, if everything comes up, I have NO idea what I am going to do with it all. I have the space, but getting the beds prepared is another story. Our soil is awful and after spending a pretty penny on soil alone for our raised veggie beds last year, I cannot imagine doing that again...at least not this soon. We bought a compost tumbler on craigslist so slowly but surely we will hopefully be able to start making our own goods to add in.