What are these white specks on this osteospermum (african daisy)?

This african daisy plant has lots of tiny white "crystals" of varying sizes all over the soil and stem, with some on top of the leaves as well (not as much underneath). It looks a lot like salt. Some of the leaves were chewed on by something, the end of one stem is brown/dying, and there’s a really thin spiderweb at the top (upper right photo). This plant was a gift, so I don’t know how it was taken care of before. I thought it might be spider mites, although I don’t see anything moving, but I’d like to make sure before I bring it back indoors. What could this be?