Biodynamic calendars divide days into fruit, root, leaf and flower according to the Moon's sign, and some wine merchants schedule tastings on fruit days because the wine is said to show better.

The scheme comes from Maria Thun in the 1950s and rests on Rudolf Steiner's earlier work. Blind tastings set up to test it have not found the effect: a 2017 study had trained tasters rate the same wines on fruit and root days and got no consistent difference. Growers who swear by the calendar tend to be doing several other things well at the same time.