Kathy McIntosh wrote:
"Jeff Layman" wrote in message
...
Broadback wrote:
I need a fair number of the above to plant up in a gravelled area. any
suggestions as to an economical source, or would I be better purchasing
from local sources?

Do you want them frost-resistant or frostproof? It's always worth
checking the labels.


What is the difference between resistant and proof? I would like to know
as I have to get a new pot for our parents grave. The last one succumbed
after 18 months, but I think it cracked under the force of the solid ice
filling rather than just frost.

Basically, frostproof means just that - it will withstand any amount of
frost. That usually means it has been fired at such a high temperature that
it is waterproof, and water cannot soak into it. As water expands on
freezing, the ice formed will crack anything the water has soaked into.
However, it might be a different story if the pot fills with water which
then freezes. If the terracotta isn't thick enough, the ice might just
force the pot apart from the inside.

Frost-resistant, IMHO, is meaningless. It is might mean that the pot will
withstand a minor surface frost, but anything penetrating could be damaging.
But what "resistant" actually means is anybody's guess, and will always mean
one level below what you experienced according to the pot manufacturer's
lawyers. ;-)

It doesn't seem to matter whether or not the pot is glazed. If you look
closely on glazed pots you will often find surface imperfections in the
glaze (bubbles?) where the underlying material is showing through. Even a
pinprick-sized hole is enough, over a period of rain, to allow enough water
to soak in to cause trouble when it freezes. And the first thing to go will
be the glaze nearest the hole, so compounding the problem.

I have used Yorkshire pottery containers with great success, although I had
one 15" half-tub crack (eventually in two places) for unknown reasons. I
could see no surface damage where either crack appeared, and where water
might have soaked in. It was also in a very protected position where a
frost was unlikely to be severe, and its three identical companions next to
it remained undamaged.

--
Jeff