Hi Hank, I thought a veg grower might have answered your question by now, Japanese onions are pretty hardy, but can be spoiled by wet, espcially in cheshire, so I would put the tunnel over them, more to keep the rain off than anything, also by doing this they should be ready for harvest a little earlier, Derek.

Thanks, derek. Will do, first thing tomorrow morning.

I overwinter mine in cell trays in the coldframe, plant out early March. They are in the greenhouse at the moment, 4 leaf stage, and will go into the frame Xmas day.