Kale transplants well when fairly young. I've moved plants a foot tall. You can plant a little deeper when you move it. Water in well until it re establishes. Red Russian self sows for me but your winters may be too harsh to rely on it coming through and flowering the following spring.

I have Kale growing in my greenhouse that I transplanted last month. It is in a wooden barrel and it has survived 15 degrees outside, not sure what temp was on inside but it was not heated. I am sure it was only around 20 or lower. I do wish I had planted it deeper. It is somewhat tall. I have also started some Arugula, Swiss Chard, Cabbage, Bok Choy and Buttercrunch lettuce that is also surviving. We just put a barrel woodstove in there today to keep it warm enough at night so they continue to grow. Today it was very nice in there with the sun shining. I think around 70 or so. Nice !

In my experience, Red Russian is the *least* frost hardy of all the kales I've grown. Winterbor Kale and Beedy's Camden Kale are the most hardy.

And Winterbor is fully hardy to at least 5 degrees. It winters over for me and produces a wonderful flush of spring greens that taste and look like small broccoli--you eat stems, leaves and buds.