aml1014
Masterpiece
I absolutaly agree that larger containers will freeze same as smaller pots AT constant low temperatures, that's nearly impossible in our climate as it can be 14° at 7am and 60° be 11am so those larger containers never freeze through until our rough month which is February and March can be hot, or very cold. It's very unpredictable. Nevertheless, larger containers do take longer to freeze then smaller containers do, that's a fact. Many places in the country can stay under 32° for weeks at a time, but we do not have that here even if the trees are kept in full shade.No. It does NOT really depend on the size of container. It's not that simple. It mostly depends on what's IN the container.
The soil in a 6 inch pot can freeze solid with no problems, just as the soil in a 24" pot can too. It all depends on the species in the pot's ability to withstand Intracellular freezes. Those kinds of low temperature come with extreme, constant lows below 15 degrees or so (this is tremendously variable). Smaller pots can reach those lows more quickly because they have smaller mass, but those same temperatures can affect larger containers as well.
A Ponderosa pine in a solidly frozen six inch pot at 0 F will be fine for days, while a Japanese maple at that temp in a 12" container will get winter kill or lose branching...
Aaron