Shagrathanswered grow question 5 years ago Hi!
I cant remember how long it takes for the plant to fill that cup with roots but I suggest that you let them grow maybe 3-5 nodes before transplanting so that they have bigger and stronger roots and they will survive the shock better.
Im not sure how cold they can handle either but I wouldnt go below 10-12 Celsius night temps and those are quite cold too.
Hopefully youll get better answer from outdoor grower