Well made special clay pots generally don't crack despite temperature & moisture changes BUT they have to be the expensive ones meant for being outside all the time. The typical garden clay or ceramic pots sold in most places can't hold up. The ones that make it through winters outdoors are often very expensive since they're made of a special clay & double fired. Occasionally, you can find a bargain but you tend to get what you pay for. I managed to buy one huge crack-proof pot for only $20. I wish I could find more. It's made it through 5 winters so far & while our climate is mild, it does freeze & I've lost cheaper pots before.

If you're interested in what sort of pots stand up to winter conditions, the best thing is to find a high end, maybe European place, that specializes in outdoor statues, ornaments, & planters & ask questions. If you buy such a pot, make sure it comes with a guarantee to not crack unless mishandled. You can expect to pay a couple hundred dollars for such containers but over time, you get your money's worth. They are available but few carry them since they're expensive. If you look at European gardens, they have old containers & urns that have stood outside for many years & are sometimes passed down to new generations. They know how to make things that last & are of top quality.

Failing spending lots of money, you could always place your plants inside large plastic pots & put them into your ceramic pots. If you allow room between the two & perhaps place foam peanuts in the space (cover the top of the peanuts with moss to hide them), the ceramic pots won't crack. It's when the clay is saturated with moisture & then freezes, the frozen water expands & since it has no where to expand into, cracks. I'd make sure any water given to the plants can drain freely out the bottom of both plastic & ceramic pots so it won't accumulate in the expensive ones.

Thanks for your thoughts. These pots are $130 each. But the salespersons in the store did not know much about them. I'm contacting the corporate office to directly ask the buyer.

If it helps any, the experience I've had with good quality outdoor pots is they 'sound' different when you rap on them with your knuckles or some hard object. Cheap pots make a 'thunk' sound like you'd expect from ordinary terra cotta.

But the good ones have almost a musical tone to them - more a 'ring' than a 'thunk'. I think it may be both the clay used & the double-firing. Think of what an ordinary glass sounds like if you run your wet finger along the rim - no real sound is made. But when you do this with good fine crystal glasses, it hums or 'sings'. It may even have to do with the density of the finished clay. Of course, you won't hear this sound when it's full of soil but when new & empty, it sounds musical, not dull.