Night frost killed seedlings in sealed jug?
Last year with the early heat and then freezing, the only thing I worried about was making sure my jugs of tomatoes were closed rather than open over night if there was a frost predicted. So long as they were in the closed jugs, the seedlings laughed in the face of frosts, seeming to be unscathed. So this year the only jug with sprouts already was my chocolate cherry tomatoes, which had lots of sprouts but no true leaves yet. Two nights ago we got an overnight frost, and when I checked them the next morning, instead of green, they were tinged with black/purple and slightly shriveled. I waited hoping the sunny day would warm them back to health, but now two days later they still look runty and sad.
Is this common that a frost will kill seedlings inside a closed milk jug? Or is it possible chocolate cherry is just more sensitive? I assumed that since it had sprouted despite the cool temps when nothing else had, that it was perhaps more cold tolerant, but now I'm just not sure.