Hi Leigh Anne,
This calendula extract I would recommend putting on the fridge (or somewhere with a slight bit of indirect warmth) away form the window yes. The main herb that does well in a sunny window is St. John’s Wort.
Another option for other cold extraction herbs, in seasons other than summer is to put the jar in a brown paper bag in the window sill to recieve indirect warmth from the sun.
Best of luck,
Benna