If it is unheated, it will probably get as cold inside at night as outside. Will the clematis survive outside at night? Why not heat it? A gh that small will cost very little to heat.

maggiepie

Why not get a small cheap heater so you can keep a large number of different plants in it to enjoy? Lowe's and Wal*Mart have them as cheap as $20. If you want to start seedlings in it in the spring it will need heat. Do you have auto vents? Fresh air is also important.

Congratulations maggiepie on your new GH. I am also zone 4 in WI. What state are you in? I would not personally keep any plants in my GH without any heat. We have such extreme temps in wintertime. Greenhouser and tsmith have good advice to go and get a cheap heater. Congrats again. Barb

Hi Terry,
Heating the greenhouse is not an option at this time, but last year I had a few little hostas and aquilegias in pots which were left in my unheated garage and forgotten for the winter.
I was very surprised to see them start to sprout when Spring arrived.
I was thinking that maybe I could do the same with things in the greenhouse.

The temperature swings in a greenhouse could be harmful to your plants whereas a garage will not have these swings. There are two very hardly plants. Why not plant them in the ground outside?

If the GH is unheated, it would be better to use a mini hoop house. It is imperative that the mini hoop house be painted high gloss white to reflect the suns heat. The link below is a mini hoop house I plan to use. You can make as many as you need because they stack inside one another for storage. They can also be put in place anytime before the early spring thaw. You want to avoid the many freeze/thaw cycles that you get in early spring. Than is when you get all the damage. John

Here is a link that might be useful: Hoop House

Thanks everyone for your replies.
I think I will stick with the unheated garage until Spring.
My biggest problem is I have a LOT of baby clematis and I think they are probably too small to put in the ground for winter, some only germinated in the last month.
John, thanks for the link to the mini hoop house, I have not heard of these before.

Clematis are one of the most cold tolorant plants thriving in the Cooperstown area of NY State. I believe that's zone 5 and bitter cold in winter. The young plants will go dormant with the first good freeze.

You might consider sinking your baby clematis into the ground, pot and all. Then the tender new root system is not disturbed and the roots won't freeze like they might if the pot is left sitting above ground for the winter. Especially if they are small pots.
You also can lift them very easily in the spring and don't have to disturb the roots or repot them.

We've had at least 6 frosts since late August, the only babies that appear to have been affected are the macropetalas and the heracliafolias.
I think I will have to try burying at least half of them and hope for the best.
Thanks for your input greenhouser.

Hello wyndyacre, gee that's a bit of a mouthfull haha!
I think I will do the sinking the babies into the ground although I will probably keep a few inside the house just in case.
A lot of them are from mixed seed so I am going by the leaves as to which are multiples although I know that's not necessarily true.
My biggest problem are the latest batch of seed which all germinated so I have about 30plus baby koreana fragrans.
They only have their first set of leaves at this stage.

Magpie: A GH that small would be easy to bundle up in a clear solar pool cover for winter and with a small electric heater, could be kept quite warm, even in the coldest winter.

If you have your GH directly on the ground, a sheet of heavy black plastic on the floor wouldn't hurt either. Better, lay down a sheet of the plastic, then some foam carpet padding, and cover it with more plastic. It will do a lot to retain heat.

Then, scrounge around for used, cheap to free, washable throw rugs that will fit in your dryer. They will absorb excess water and add additional floor insulation.