I expect to freeze the Kale if that will work.  
I don't have a cold frame but plan to build some tunnels to grow under.  
I wonder how much energy a heat light will use in a greenhouse. I do know I can feel it in the back room. It's not warm but the temp is up. I have chicks in there with one heat light. I'll have to buy a thermometer to hang in there and keep a record.
One thing about homesteading I think is to keep good records. See what works and what doesn't.  Am I right?  
I tried to keep a record of what is in the freezer but that didn't work out to well. I may try again.  
Anyone here in the North have a "cold room"?  I thought I might build a small room in the garage for cold storage. With insulation it might keep cold but not freeze?  Then perhaps stick a small air conditioner in for the summer months to maintain a low temp but not freezing cold. Maybe 50* degrees would be good?  A root cellar won't work here. It's too wet. It would flood.
How damp is too damp?  Our basement is cooler of course but how much humidity is too much?  We don't use the basement for anything other than the furnace and hot water tank. We have a sump pump.  
Anyone can answer these questions or offer ideas or opinions. 
TTFN, 
Rancher