I found heaps in any crates/barrels/trunks/wardrobes/dressers from any zone. There's not really a specific location where you farm these, just that they are subject to RNG.
Produce containers generally have a higher chance I've found. I still do find them in barrels, sacks, and crates all over the place. Still, if you're strapped for time, run through the produce containers in an inn or at a grocer's cart. Most major cities have both of these available.
As Qyrk already said, there is no zone where they drop more frequently.