I just now yanked the 'cover' off one of my blue javas; there was barely any frost damage at all, way less than when I went with a more elaborate "tent".
We used a 3' diameter cylinder of 6" square mesh concrete reinforcement 'screen' with some Agribon covering over it.
I was expecting the p-stem to freeze down to the ground but there was hardly a half-inch of mush on the cut end that needed trimming.(I had whacked the 6" dia. p-stem down to 4' tall in Dec.)
Our "greenhouse" is made out of "bubblewrap" though (solar swimming pool blanket, actually).
