Knowledge · The moon’s course

Ascending and descending moon

The moon does not only run through its phases of light — it also climbs higher in the sky and sinks again. This rise and fall is called the moon’s course, and in the biodynamic calendar it decides when to harvest and when to plant.

Two movements that are often confused

The course: the path

What changes: How high the moon stands in the sky.
One cycle: A good 27 days, from the highest stand to the lowest and back.
How you see it: By its height above the horizon, not by its shape.
The words: Ascending and descending.

The phase: the light

What changes: How much of the lit side can be seen.
One cycle: A good 29 days, from new moon to new moon.
How you see it: By crescent, half moon and full moon.
The words: Waxing and waning.

An ascending moon can be waxing or waning — the two movements run independently of one another. Three specialist calendars warn of this confusion in their own editions.

What the moon’s course is

The moon’s orbit is tilted against the celestial equator. So on some days the moon stands high above the horizon and on others low over it — just as the sun does over the course of a year. What takes the sun twelve months, the moon manages in a good 27 days.

When the moon stands higher from day to day it is called ascending; when it sinks, descending. The calendar marks the turning point upwards and the one downwards in their own right.

Ascending is not waxing

The waxing moon grows brighter, the ascending moon stands higher. One is light, the other path. Both movements run at the same time and independently: a waxing moon may be descending, a waning moon ascending.

The confusion is so widespread that several specialist calendars address it in their own editions — the Spanish Thun edition twice over, and with it the Czech edition and Demeter Polska.

What hangs on it in practice

Biodynamic practice puts certain work into the ascending moon and other work into the descending one. Ascending counts as the time for harvest, grafting and cut flowers; descending as the time for planting, transplanting, pruning and compost.

Behind this stands the picture of the rising and falling sap: with the ascending moon the sap is placed in the upper part of the plant, with the descending moon in root and soil. By this picture one harvests rather in the ascending moon when the crop should stay fresh, and plants rather in the descending moon when the root should take hold.

Root activity follows the same picture: the descending moon counts as the time in which the plant works downwards. Repotting, feeding and pruning are therefore preferred then.

For the winter pruning of trees and vines, Pierre Masson makes a distinction: pruning in the descending moon strengthens weak plants, pruning in the ascending moon checks growth that is too vigorous.

Nodes, perigee, apogee

Twice in each cycle the moon crosses the plane of the earth’s orbit. These two points are the lunar nodes. The biodynamic calendar keeps them as hours in which nothing is sown and nothing planted, whatever the day type.

Also twice in each cycle the moon stands closest to the earth and furthest from it: perigee and apogee. The calendar counts the perigee as less favourable for sowing. Around the apogee it shows an impulse towards flower when the moon stands before an earth or water constellation. Both are astronomical points and have nothing to do with the rise and fall — the moon can be ascending or descending at perigee.

Frequently asked questions about the moon’s course

What is the ascending moon?

The moon stands higher above the horizon from day to day. A rise and fall together take a good 27 days. In biodynamic practice this is the time for harvest, grafting and cut flowers.

What is the difference between the ascending and the waxing moon?

The ascending moon stands higher in the sky, the waxing moon grows brighter. One is the path, the other the light. Both run independently: a waxing moon may be descending.

What is done at the descending moon?

Planting, transplanting, pruning and compost. By the picture of the sap, the plant is then working downwards, into root and soil.

How long does one course of the moon take?

A good 27 days from the highest stand through the lowest and back. The phases of light take a little longer at a good 29 days — which is why the two rhythms shift against each other.

What are the lunar nodes?

The two points at which the moon crosses the plane of the earth’s orbit. The biodynamic calendar keeps them as hours in which nothing is sown and nothing planted.

What do perigee and apogee mean?

The perigee is the point at which the moon stands closest to the earth, the apogee the furthest. The calendar counts the perigee as less favourable for sowing.