Dormancy in mini greenhouse?

[weezer]

Hi..I put my cp's in my mini greenhouse.You can see the similar one in that picture. I placed it in my balcony. I live in Turkey.In winter the coldest temperatures in my city are -8,7°C (In february).There are sarracenias in my greenhouse.I heard that they are the most durable cp's to cold weather.There will be a problem during dormancy in greenhouse at outside?Apart from the sarracenias (titan,farhamii,catesbei,flava) i put it in it my nepenthes ventrata.Here it's hard to grow it.Because it needs more humidity.I thought that in greenhouse , it will be better.But in winter there will be a problem for nepenthes staying at outside? I'm waiting your advices and comments.. Thanks..