Advice for a winter only green house

I do not have room to make a permanent green house but I do need one to over winter a few plants and maybe start vegetable seeds in the late winter. I used to say that where I live there isn't much of a winter but this year has changed my mind. I have lost some potted plants that I have had for years outdoors and next winter I want to be prepared and move them into a green house.
Questions:
1. is it ok to place the green house on a cement patio (best sun, only place with any room)
2. can I build one that is cheap and easy to bring down and store
3. what is the best type of heater to use and the safest
4. what materials work best when in a windy area

Any help would be appreciated.
Cheryl

What size will you need?

My greenhouse is a permanent structure on a concrete slab with no problems, but make sure it is secured so it doesn't blow away in high winds.

I am thinking about something small, maybe 5x3 with a 5 foot height. It really depends on the cost and where I decide to place it. I was looking at those premade greenhouses but am wondering if they are sturdy enough.
Cheryl

5x3x5 is a very small one,not one for very large plants,or one you could walk in.
That case,I just build one,out of wood,with a wire or pvc greenhouse type hoop roof.
Wood frame at the bottom,wood corner post,the arch heavy wire or pvc in a arch hoop style roof,cover with plastic.

If you're looking for something winter only, may I suggest Joannabanana's idea of using an old swingset with plastic over it? I'm looking for one myself, thinking that I'd spraypaint it so it wouldn't be an eyesore and use it for hanging pots in warmer weather. That, or if you're handy at all, you could probably rig up something in the same shape with some lumber and those metal brackets that people use to make saw horses out of. Or if you have a covered porch, you could section off a piece of it with the plastic.

Probably the only problem with the concrete is moisture retention and staining it - if you elevate your pots you should be fine on that one. The moisture... well, you can ventilate, it depends on what kind of structure you end up with.

Any of those ideas sound reasonable?

Well yes and no, I don't have room for a swing set so that is out. It did occur to me that I have an area between the house and a little wooden shed that I might rig up next winter but it does not receive full sun. I just need enough space to keep my tender plants (brugs etc) alive and so it needs to be heated in some way during our usually short cold spells. Not handy, at least not if something has to be square and plum but I am cheap so I do often find free or inexpensive solutions. I did see some interesting pics of people who used shed frames and I might try that. My biggest problem is space. my yard is not terribly small but the way its laid out makes having a permanent green house structure a problem. It's also so hot here for much of the year that I cant imagine using a green house all year round. I have until next winter to plan and figure something out. I have found some good information on this forum.
C

Well, the smaller you keep it, the less you have to heat, that's for sure. It kills me that I heat the spaces far above the plants while underneath (on benches) is cold. Grrr. Have you thought about tunnels - kind of like a mini hoop house?

There's about as many ways to heat it as there are people on this forum, lol... I personally had a bad experience with a kerosene heater, it did some leaf damage on some vegetables I was growing last year, and it's not particularly cheap, but nothing really is. Some people use space heaters, even light bulbs.

There are a lot of different threads, I'd breeze through and look at as many pictures as you can.

This is my first winter w a greenhouse. I bought one from a place called Flower House; it was relatively cheap and I set it on a cement slab. So far, this winter being colder than usual, I've started just about everything that needs to be ready by May 1st, some potted already but all still small. The only thing that I can't pot is the red onions and they are needing to get out of their starter tp holders but I don't know what to do with them - certainly can't pot THOSE !! I heat it with a space heater that has a remote and a thermostat as well as a timer. I just set it at 70 as soon as the sun is setting and leave it there til the sun hits the greenhouse at 8:48 a.m. My beds in it were originally "table gardens" and hold soil about 8" deep. under them I have shelves on the sun side which hold my starters and potted impatiens,begonias & my carrot and onion babies. Hoping to get those out soon. Any ideas on how to keep the outdoor gardens warm, anybody?

Plastic row covers,with plastic gallon milk jugs of water,among your plants,will keep them warm to a degree,as long as the temps don't drop to low between freezing,for any extended time.

http://davesgarden.com/community/forums/fp.php?pid=7500653 - just a visual of the structure I was thinking about, only covered in plastic. The metal tops are marketed as diy work- horses at the big boxes, they slip over the ends of two-by-fours and clamp onto a cross two-by-four.

I don't know how to set up a link, but there is a picture of my GH, a friend designed for on the fuschia forum. You will see it about maybe 6 threads down. It is in my breezeway. Today it is 6 deg. outside, and I have a garage heater (electric) the exact same item listend on several garden equipment sites as a 'small grenhouse heater'-only diff. is the cost $19! Right now the GH is staying consistently around 65, breezeway temp is 14. Used 6 mm poly. My friend moved my outdoor potting bench inside and built 2 small benchs inside for me. It's tight to move around in-6ft tall (for hanging plants), by 5'.wide, but gives me enough room to over winter plants. The floor is lino over cement but I haven't had any problems since the plants are on the counters, and the heater is on one of the small benches.

AND it is portable. A couple screws come out and it will be down for the summer---waay to hot in the breezeway then, plus I like my space out there.

Interesting idea, I need to find a creative solution like that. I have a little patio off the kitchen that probably could be temp. enclosed for the winter, problem is 2 dogs use that exit to do their thing in the back yard. Still your idea has made me think in some new directions here. Thanks for all the information and inspiration. I love looking at peoples project pics.
C