Hello Friends,
Just want to ask if unheated garage is better or greenhouse for potted fig plants for winter?
Thanks a lot!

It depends on a few things... will the greenhouse be going up and down in temperature very much?  You don't say whether or not it'd be a heated greenhouse, i.e. one that has some additional heating (in addition to passive solar heating) as a means of keeping it from getting too cold.  In Staten Island, if it's an unheated greenhouse, you could get temperature variations ranging from below freezing at night to plenty warm enough to stimulate new green growth on a warm day with lots of sun.  If that's what you're looking at, that would not be good for your fig trees... they'd get some new tender green growth going, followed by freezes that could be fairly prolonged, and would undoubtedly damage the trees.  So if that's the kind of setup you're talking about, I'd recommend the unheated garage instead.  Keeping the trees out of the wind is half the battle... cold dry wind is one of the killers.  Don't get the soil too wet and soggy, because they don't need much water when they're dormant and cold (just a little bit moist to prevent desiccation) -- freezing of wet soggy root zones is another killer.  It's unlikely that the unheated garage there would get so cold as to kill them.  (This past winter notwithstanding... as we've seen it can happen, but it's been fairly rare).  So if you're worried that it'll get TOO cold in the unheated garage, you may find a few ways to supplement the available heat... if you have electricity there (or can reach it reasonably with a cord), then some people have used strings of christmas lights strung over the trees (possibly with a tarp over them) to provide small amounts of heat... it's usually enough.  Others (including me) have put some 250W incandescent bulbs into ordinary light sockets, just enough to raise the temperature a little bit.  There are other choices for supplementing with small amounts of heat.

So if the greenhouse option is an unheated one, then I'd suggest the unheated garage is a better choice.  It might be different if you're talking about a more substantial greenhouse with a more sophisticated temperature control system that would prevent wild swings in temperature.  Also, I'm tuning this answer to the climate in Staten Island, NY.  For other locales (warmer) the answer could come out differently.  It depends on how much temperature variation you're likely to get in that greenhouse.  (And by the way, even if you do have a sophisticated greenhouse that can keep it nicely warm throughout the winter, I'd still recommend that you let the trees go dormant outside for around 3 weeks anyway).

Hope this helps.  If you're looking for more tips on winter strategies, you could search on older posts on this forum... a few years ago there were some good bits of advice.  Look for the info that robertharper posted, among others.  

Mike   central NY state, zone 5a

You gave me excellent advice Mike! My greenhouse is without supplemental heat. I will put tress in garage.
Thanks a lot!

Mike,  Those are good questions you raised for an unheated greenhouse. 

I am considering a coldframe greenhouse to grow in ground trees.  Will train to low cordons (step over) so easier to cover.
Controlling the temperature during summer looks easier than through the winter.
I wonder if covering the fig trees in the greenhouse can address the 2 winter challenges of protecting from the bitter cold at night and buffering the heat that may build up during sunny days?  If necessary I can provide ventilation.

I put 4 inground in my 10x12 glass greenhouse this summer. I plan to put up a dark tarp on the inside frame to help block out the sun for the winter to keep the temps from getting too high. I plan to wrap them individually as well.
Tyler

Tyler
Interesting idea.  Hope it works out!  
I would think for the figs to break dormancy they would need a hot temperature >10C for an extended time.  Hopefully just a few hrs during the day may not be a problem. 

Mike,

Be careful putting a 250W incandescent into a regular light socket.  Most of them are rated to 100 or 150W, some are rated much less, meaning it could start a fire.

Hi ik2003,
In the garage the trees will sleep in a big volume of air . So if you're not leaving the door wide opened too much, it will work.
In a cold greenhouse, you'll have to monitor heat from the sun and humidity . Remember that humidity + warm temps = Rot on trees . You'll have to vent the gh automatically or manually.
The volume of the cold greenhouse is important . how big would it be ? In small volumes, you would easily toast the trees on sunny days. In bigger volumes, you'll get better temp control and less temp swings.

Thank you everyone!