Cold Frames and Mini Green houses - what's the difference?

I have a couple of mini green houses - the kind that have clear plastic zipped over a metal frame. They also come with a shade and frost cover. I've only used them (with the clear plastic) as seed starters in the early spring. I understand that cold frames are used to harden off seedlings...is that correct? Could I do the same thing with the mini greenhouse if I used the shade cover slighty open or kept the clear one unzipped? In other words, trying to save space and money, what other benefits would a cold frame offer other than space for larger pots?

Cold frames are very low on the ground constructions, like a raised bed, empty of soil, but has a clear glass roof on it, this is normally a space used between the greenhouse treatment and just before the plants are tough enough to get set out into the garden, in other-wards, like a midway house, I use mine all the time early spring as the air/ground and temp is too cold for plants right out the greenhouse where they have been molly coddles since germination.
Depending on what and when you start your seeds off, but for me, I start most seeds FEB/March, after germination they are set into small individual pots and remain in the greenhouse, by end of April, the hardier plants like cabbage, peas/beans and other hardier veg can be hardened off in the cold-frame, with the glass roof open a few hours longer each day, by end of april, they are hardy enough to go into the garden, but I live in UK and even in early May, we can still have night frosts, so my cold frame allows me to make more space within the greenhouse and still protect the baby plants if need be in my cold frame. if I am late starting some veg seeds, I can start them off in the cold-frame in March / April as the frame just protects them from frost and cold winds, by March /April the greenhouse is bursting with seedlings of more tender plants that cant yet go into the frame and need much longer in the greenhouse, like summer bedding, my Fuchsias/geraniums etc that here, need a longer spell in the greenhouse to survive and become large enough to plant out end of May, I also need room in my greenhouse for protecting exotic plants to us in UK like Passion flower, etc, we can grow many things as indoor plants that most of you folks place outside all year round, these take up room till I get them outside for a few weeks in summer. hope this helps you understand the different ways of using both these protective areas. good luck. WeeNel.

Thank you WeeNel. It sounds like I may need to invest in a cold frame as I get more confident. Happy gardening!

Hi Hankinsv, the good thing about a cold frame is you can extend this or just make another one to sit side by side if you need more space and you dont have to spend a lot of money to make them, you can winter line them using old polestirene package stuff if you get really cold winters down your way, I lay sand (about 4 to 6 inches deep in the bottom of Horticultural sand from B7Q building dept) about £3.00 per bag, this acts as an insulator from ground frost but allow for this extra depth if you build your own. As for the greenhouse, these are very expensive and would recommend you buy the largest one you can afford as you will soon realise just how many different times of the year you will use it, winter seeds, storing tender plants and of course, heading away from the troubles and strife of family and the world, I would go to the library if I were you to look for books on the workings and where the best place to site this expensive playhouse Ha, ha, ha, but you can do without this till you learn more about all you want to grow and propagate etc. Good luck, have fun and enjoy. WeeNel.