i use a plastic pot inside the glazed pot so i can lift the plant out in fall ... and store the pot properly ...

there is a potential to crack.. when wet media in the pot expands.. as it freezes ... so you would want to let the media dry toward late fall ...

a good way to water in winter.. is to just add ice cubes or snowballs to add measured amounts of water ...

though in z6 ... im not sure your plants would need to be stored indoors in winter ...

same for whether the pot will break in z6 ... does your ground freeze ... will a pot actually freeze solid.. like it might for me .. in z5 MI ....and what are the odds that you will have that every ten year ... z5 winter ...

glazed a compared to non glazed.. is that the glaze is supposed to not allow the clay to get wet [besides the fact that it is fired, or course] ... so the pot itself is not wet in the interior ... if properly glazed/fired ... that pot should be water repellent ... and this should be a much lesser issue ..

it really comes down to how much $$$$ you have invested in the pretty pot .. and whether you are willing to roll the dice ....

ken

Don't know much about pots but the inside is not glazed, terracotta color. Not sure if that matters. The pot is huge, so it will never be moved once it's placed and the plantings won't be planted in the ground during winter either.

The pot is huge, so it will never be moved once it's placed

==>> and that is why pot in pot.. would be perfect ...

media is the most important thing in a pot ... and it wears out.. after a few years ... and since its your water management system.. you dont want it to wear out ...

soooo... if you can lift the smaller pot out.. and change out the media... in 3 to 5 years... all the better ...

im not a ceramics guru ... but i think the important part.. is whether the pot was fired ... and i will leave it at that.. since its all moot since apparently you bought the largest pot on the face of the earth... lol ... and you arent going to store it anyway ...

ken

Solution- return the pots. Not worth the risk or hassle

There are "frost proof" pots, but even those will crack if left out all winter in the right conditions. It's not so much if its glazed or how it was fired. It's the fact that if the soil is packed densely and the water in the soil freezes, the entire volume will expand and cause a ton of pressure, and crack the pot. Not a ton you can do about this. The only way you can leave the pot outside safely, is if it is empty.