Croatian pomegranates do not ripen on my chest of drawers given around six weeks of time under non-laboratory conditions.
Figure (a) below shows the pomegranates when first picked along with cut-away of an example from the batch which was later disposed of. Figure (b) shows the pomegranate after six weeks of ripening time on my chest of drawers in my bedroom. (Note different coloration is possibly due to dissimilar lighting conditions, or possibly not.)
Pomegranate shell had hardened and dried over time making them difficult to cleave, however a suitably sharp bread knife was able to finally cut the fruit.
This result shows that it is unlikely to be worthwhile holding onto pomegranates which are note yet ripe as they are unlikely to redden after picking. This is unless the fruit tested are not actually pomegranates, which may well be the case since the test batch was harvested from an unverified source.
I would like to acknowledge M. Arnold and D. Mager in participating in this research and for also providing good times this summer.