I grated 2 rootstocks at the grafting class. One took nicely and 1 did not. I had put a couple pieces of scion wood in the vegetable keeper of my fridge wrapped in damp paper towels & a zip lock bag. When I retrieved the bag the paper towel was frozen!? My question, is the scion wood still good as it most likely froze too? I’d like to try another graft to the rootstock which is alive and well. Tim