We have almost no evidence about what the Norse actually did for Summer Finding as a religious festival. However, one can presume that the return of growing things, planting, fertility, Freya (Goddess of love, sex, and women's magick), and perhaps Sunna the sun Goddess may have been involved. Though planting may have been delayed (if done at all) in the far northern provinces of Scandinavia. Landwights (or spirits of the land) may have also been honored at this time.
March 21st is pretty much one month earlier than the earliest planting in the southernmost and most fertile areas of Norway. And that's with modern technology, chemical fertilization, and global warming.
I'd think they'd be more interested in celebrating spring equinox for its own sake, than fertility and planting.
