The European Tradition of the Lunar Gardening
As far as the European tradition is concerned, it is associated with the name of Rudolph Steiner. The essence of the difference lies in the fact that this tradition does not use both the Tropical Zodiac and the Sidereal Zodiac. Instead of that it uses constellations.
Constellations and Zodiacs
I have tried to find out where the borders between constellations are and how we should know in which constellation the Moon is situated at any specific moment. But it was difficult to find the answer. Finally, I came across some information in The Biodynamic Sowing And Planting by Moon Lunar Calendar by Maria and Matthias Thun. It was told that there is an hour when the Moon comes into every constellations during the year 2010. If I take the average of the Moon's position for different months, I will be able to understand where the borders between the constellations are situated. Later, if I come across some more sources of information, these numbers can be made more precise.
However, Nick Kollerstrom , an outstanding astrological researcher, the author of "Planting and Gardening by the Moon phases" argues that irregularity of constellations causes an imbalance in the energies available to the gardeners. Here is what he says in the book:
“The trouble began when Maria Thun imposed the four elements on to this irregular set-up in the 1950s. Her use of these divisions made for a radical imbalance in the four elements. Root days (Earth) were assigned over 50 per cent more of the month than the Flower days (Air). The Air-constellation Libra is very short while the Earth-constellation Virgo is two and a half times longer.”
Nick Kollerstrom says that we would rather use the Sidereal Zodiac instead of constellations. The Sidereal Zodiac is made of Zodiac signs of equal size ( each taking 30 degrees of longitude). This is its difference from the constellation.
The Sidereal Zodiac differs from the Tropical Zodiac ( mentioned in the American tradition) in the point of origin, and they contradict each other due to this matter.
Because of this 23 degree difference it often happens that according to the Tropical Zodiac, the Moon enters one sign( for example, Aries), but according to the Sidereal Zodiac it is in Pisces. That is why there is a difference in the way the Lunar Gardening Calendar and the Universal Lunar Calendar tell the time when the Moon entries the signs.
The current version of the Lunar Gardening Calendar is based on the Sidereal Zodiac. In a later version I will add an option of switching to Steiner's constellations.