you need to keep ya roots warm if possible the purple ya see in the pic could be Phosphorus being locked out from cooler temps.you'll also get really slow growth as well in the cold.don't think they will die or owt just stunted growth..imo

have you a heated prop or heat mats to put under the pots in veg..take it ya not using hid lights cos they would warm ya room left on 24/7..just a thought man gluck..