This shows the danger of too rigid adherence to traditional knowledge but in this case had the curious result that the tradition was pre-adapted to present-day climate changes. The solution to the mystery is found in the history of our calendar system: Pope Gregory VIII arranged a calendar reform in 1582, whereby the differences of the Julian calendar could be corrected to the sun year to a large extent. The day of the “Cold Sophie” (15 May) was the date in the old calendar and corresponds to today’s 22 May. Therefore the effects of the “Ice Saints” were traditionally felt in the period 19-22 May. (Today’s warmer climate means that the new saint’s days earlier in May correctly predict the period of cold spells). Sensitive transplants should only be put in the garden beds after this date. (