You should really consider how well your plants are going to do in their north facing interior after they've been brought in from any greenhouse you might purchase.

Some plants "learn" their environment, and so thrive on what's available, many/most don't. Surely you don't want sickly looking plants insider during the majority of the year?

Bottom line, a greenhouse might help you keep some species alive year round, but unless you plan on sitting in your greenhouse looking at them, it may not be to your advantage.

Cheers,
Russ

Ha, thanks for your bluntness! I purposely tried to buy lower light plants, and I do have a few western-facing windows, all of which are now hosting plants.

I do enjoy sitting and looking at them, but I appreciate seeing their growth more, so you're actually encouraging me more to investigate greenhouses!

First determine size you'll need,always go larger,trust me on that one!!!! Placement outside where it will be,sunny or shaded location,sounds like probably shaded being low light plants,how much your wanting to spend,this should put you on the right track,also will you have help putting it together.