I have some pinus parviflora I keep indoors, but do they need some cold weeks outdoors during winter to grow properly?

massai wrote: I have some pinus parviflora I keep indoors, but do they need some cold weeks outdoors during winter to grow properly?

Not only do they need 'some cold weeks', they need the right climate, year round.
Pines do not belong indoors.

Thank you for the reply. Unfortunate indoor bonsai is my only option, so I have to make do with that.
I will try to ask a friend if he can have my pines for a couple of weeks of winter holiday.

indoors your pine will die. You really should give it to someone else and if you really can only have indoors, consider ficus or possibly chinese elm. Most other species will die over time.

I agree with the others, indoor your pine will die!!