sowing outdoors in freezing temps

[PyreneesPlot]

I sowed summer cabbages a couple of years ago in trays outside which then froze solid. A few weeks after thawing I had 100% germination. A fluke, I suspect!

[alldigging]

I've checked in the greenhouse today and found some seeds poking their heads up!
Portuguese cabbage is one (and I will have to get my seed book out to see what else I planted lol)