I have semps in pots, in my balcony as well :) We've already gone through freezing weather, down to -3c. I think they can stand upto -40 as long as theres no water in the soil when freezing.

I have many semps in pots for many winters, mind you not on balcony. If drainage is good, they survive the winter without any problems.
Have bigger problem with clay pots cracking...so keep most in plastic. Found some with bare roots in the spring, and they lived (either pot overturned or squirrels were digging).
Photo of couple of pots after last winter.

Rina

This post was edited by rina_ on Tue, Nov 12, 13 at 13:33

wow beautiful.

Thanks for answering, NameTaken & Rina.
Wow, those are beautiful Rina. While mine have been multiplying, the big pot is not that full yet. The larger pot is plastic, so I'm guessing it's ok. The two small pots are terra cotta, so I'll have to watch those.
I guess the trick is to check the weather and only water if it's not going to be freezing that night? Or only water a little bit in the morning so the soil is dry by the time the temp drops again? I know they need less water in the winter, but they aren't where they can get rain/snowed on, so I don't want them to dehydrate completely.

Now I cant tell you from experience since this is also my 1st winder with semps. But thats how Im going. Its been 3 weeks since Ive watered them and its time for a watering. Last night and tonight the teamps are below freezing, so I will wait till tomorrow to water. As next entire week its above freezing.

You could water in the morning but I dont know how fast the water will drain and dry out. So to be safe, I will just wait and see if the next day or two is above freezing and water them.

I don't water them at all, they get whatever rain/snow falls on them.
They are all in same containers for few years, year round.

I realize that yours are on balconies, so it's bit different. Are there roofs? or balcony mostly enclosed? Do you get any snow falling on the balcony?
Here are few photos of more semps in containers I have:

concrete container:
{{gwi:94264}}

plastic-shallow, it's a plastic saucer:
{{gwi:94265}}

concrete home-made container:
{{gwi:94266}}

plastic pot:
{{gwi:94267}}

this is clay square container I have for about 6-7yrs, it has one small crack now & it's 'stuffed' with semps-have to divide:

glazed clay-actually a large bonsai-style shallow pot:

clay:
{{gwi:523113}}

plastic:
{{gwi:523115}}

plastic:
{{gwi:545935}}

The pots are exposed to elements, few are sitting amongst other plants in beds, some are on deck, some on patio. They all have good drainage - free draining soil and drainage holes.

Last photo: plastic.

Rina

This post was edited by rina_ on Wed, Nov 13, 13 at 20:44