"Witches were active on the
eves of St. George’s day and Midsummer.
Then they were wont to go out and cut chips from doors and gates of the
farmyard and boil them in a milk pail, and in that way charm the milk from that
farm. Their plans might be
frustrated, however, by carefully smearing the newly chipped places with mud."
[and I think that superstition was invented by a canny farmer as a way
to get his chipped doors repaired immediately by the hired hands]
There is another
superstition that Evil Spirits are abroad at midnight on St. George’s Eve, but
that seems to be connected with his festival day in May.