Magmaberries that only grow over 100F.
Frostroot that only grows below freezing.
Would have similar nutritional value, but increased trade value, or perhaps other interesting things like producing meat items or such...
would need to set spoil limits. though sounds like fun.
If there is a way to do this in the XML I haven't found it yet. I was wanting to add snowberries to my Xtra Plants mod but there is no designation for which temperatures are preferred by each plant. It's probably possible to do with a .dll file but I'm nowhere near talented enough with C# to attempt that.