Hey Pete. I wouldn't go so far that they won't survive - but only that you may lose some if the winter is too wierd. I think the idea of burying pots in the ground is a good one. But here's a pic of the flat I've been using for about 5 years now, and most years the survival has been quite good whether I sowed thickly or spaced carefully or whichever. The flat is an old DFO fish tray - it's about 2 1/2 feet long I think and 2 feet wide, about a foot deep. I mulch with kelp most of the time - just a heap of the raw stuff from the beach.
The survivors here are the bulbils I planted out in the fall same time as the garlic. They're getting close to ready in spite of the late start to spring here. The lower leaf is starting to yellow, and they're starting to flop down. My porcelain scapes were just ready to harvest yesterday, and bulbils are usually ready in a week or two from now, maybe ten days before the garlic is ready to harvest.
Wireworms are a curse!!!
I need to get some mustard seed too.
I hear that radishes make a good trap crop too, but the beasts have such a long life cycle (6 years or something!) it can take a lot of work just to get the population down to manageable if they're bad. I know they love potatoes...