Taking the plunge - my first greenhouse

Well, guys, I'm taking the plunge (or planning to, anyway) and need some help and ideas. I'm moving in August/September to a new apartment with a balcony, and I want to build a makeshift greenhouse out on the balcony for my cacti and succulents. Being on a student's budget, this is not going to be an extravagant affair - I'm thinking along the lines of some 2X4's for a frame, and some thick plastic walls, with a floor model housefan for ventilation. Does anyone have any ideas - like whether or not this cockamamie plan is worthwhile at all, and if it is, what kind of things I should take into consideration when building it? One of my biggest considerations is that without a heater, I wouldn't be able to leave my plants out there through the winter, and that in order to climatize them gradually to room temp. again in late October/November (or at least by the time the snows start), I'll have to transport the whole greenhouse into the livingroom for a little while until the plants are used to room temp.

Any suggestions are welcome!
Thanks, guys,
Shelly

Shelly,

You're plan is very workable. I should think that you could use a portable heater with a safety shut off in the winter months, and during the nights you could throw some sort of insulating material over the top, like thermal blankets, of course you would turn the heater off at nights, but the blankets should hold in the hear.

Jerrie

I don't know pices...I am in 4b too, and it can get down to the single digits (farenheight) here... I don't know if a greenhouse can hold heat without a heater through those temps. Does anyone know? I'd love to make one myself, but had the same concerns...

-plant girl :)