I am in the PNW, and my winters are not very harsh- usually. Last year I took a chance and put a few small yacon crowns in my coldframe and they made it! I was pleased to discover this. I won't be leaving all my crowns out in the weather though, just in case.
I have yet to harvest my yacon this year, but I am particularly excited to see how a volunteer plant (on its second year) will produce and how it tastes. The other varieties (three types) I put into the regular vegetable garden this season in mounded beds. Nowhere near as good of growth, at least size-wise.
The seed grown yacon is there by my chicken coop in a makeshift, hopefully easy-to-harvest "planter". 2x4 mesh metal fence stuff? Made into a circle. Inside- lined with cardboard and filled with compost, old potting soil and such.
Just pull away fence and hopefully most of the good eating bits won't be too stuck in the ground!