Maria Thun

Who was Maria Thun?

Maria Thun (24 April 1922 – 9 February 2012) was one of the most influential research figures of the biodynamic movement. She grew up on a farm near Marburg and came into contact with biodynamic agriculture in the 1940s through her husband, the painter and anthroposophist Walter Thun. Over decades she carried out systematic growing trials, with a persistence in repetition and documentation unusual for her time.

Her name today is all but inseparable from the sowing calendar: millions of gardeners, far beyond the biodynamic world, know the division into root, leaf, flower and fruit days that goes back to her.

The sowing calendar

Thun investigated how the position of the moon in front of the twelve zodiac constellations bears on plant growth. From this she developed the division of days into four types, still influential today, each assigned to a part of the plant — root, leaf, flower and fruit days. Her thesis: on a “leaf day” (moon before a water constellation) leaf vegetables do particularly well, on a “root day” root vegetables, and so on.

In 1963 she published her first sowing calendar. It has appeared annually ever since, is translated into many languages and is among the most widely used tools of biodynamic timing. Barrel compost also goes back to Maria Thun — a prepared cow manure compost with basalt powder and compost preparations.