Ms.Iris,
just in case in my last e-mail I stepped on your toes,
please accept my most humble apologies.

My feet are of clay, with totally impervious toes. Not to worry. I suppose I
was oversimplifying again. I think for the average amateur bonsai grower, the
important thing to remember is that junky pots are more likely to crack than
good ones, especially if they are exposed to freezing. And a good soil mix
which drains properly is more important than the exact type of pot. I have put
trees in the ground for the winter, here in Zone 5, in "unglazed" brown pots,
and they were fine. The pots were fine. I would not put a tree in the ground
for the winter in an expensive pot, a pot glazed on the inside, or a porcelain
pot. If the tree needs to be outside for the winter, in most cases you can slip
the plant out of the pot & put it in the ground, and pot it up again in the
spring. If you're not sure, you can usually store the tree in the garage or a
similar location.
Iris,
Central NY, Zone 5a, Sunset Zone 40
"If we see light at the end of the tunnel, It's the light of the oncoming
train."
Robert Lowell (1917-1977)