The Synodic Moon is a celestial cycle otherwise known as the full moon to new moon cycle which relates to the moon’s position relative to the sun as seen from Earth. It is the lunar cycle we are most familiar with because it governs which –if any part of the moon – is visible to us. This is due to the combined effect of the sun’s light and the earth’s shadow from different angles on the moon’s surface.

The full moon to new moon cycle lasts 29.5 days during which the moon appears to increase in size when it is said to be waxing, and to decrease in size when it is said to be waning. The cycle begins with new moon, when the moon and sun meet in the sky because the moon is right in front of the sun as viewed from earth. As the moon is reliant on sunlight to make itself visible the new moon is invisible from earth (except during a solar eclipse). Astronomers call new moon an example of a sun-moon conjunction, a conjunction occurring when two celestial bodies conjoin in the sky. The period marked by a planet returning to the same point in relation to the Sun is called synodic, after the Greek word synodos for meeting. The synodic period between new moons is the basis for our calendar month. The meeting of sun and moon at new moon symbolized copulation to the ancient Greeks, who saw new moon traditionally as a time of fertility and rebirth.

After several days, the waxing crescent of the moon becomes visible, with the left or western side of the moon illuminated in the southern hemisphere, and the right side in the northern hemisphere. Some interpret this crescent as resembling the upward pointing sprout of a newly germinated seedling. At first quarter, half the moon is visible, rising around midday and setting around midnight. The waxing moon is then said to become gibbous, with only a small portion in darkness. At full moon, the sun and moon stand opposite each other and the moon reaches its greatest extent as seen from the earth. As the moon rises, the sun sets. Astronomers call this an opposition, when celestial bodies stand 180 degrees opposite each other. Full moon is traditionally seen as a time of bounty, the small seedling having reached its full expression. Then the moon begins to wane and seems to diminish in size, initially waning gibbous and then moving into last (third) quarter when it rises at night and sets at midday. The cycle is complete when the waning crescent is invisible at new moon.

Biodynamic farmers believe the moon’s influences on earth are felt through the medium of water. During the waxing moon there is an increase in the moisture content of the earth and atmospheric humidity. This helps plant growth but may encourage fungal diseases. These can be kept in check by spraying horn silica 501 or common horsetail 508, and by avoiding opening the soil by ploughing (which may also encourage weed germination). On the plus side, soil moisture during the waxing moon period makes this is a good time to spread solid compost, or apply dedicated soil sprays like horn manure 500 or Maria Thun’s barrel compost 502-507, and even liquid manure sprays intended for the soil

Farmer’s lore holds that rain is likely at or soon after full moon. This may explain why years in which there are thirteen as opposed to the more usual twelve full moons are supposed to be lesser years for wine. The timing of the full moon may influence biodynamic farming decisions, encouraging growers to speed up grape picking, for example, in autumn, or to spray the vines pre-emptively to prevent fungal disease attack during the growing season.

Growers of annual, above-ground crops from seeds are advised to sow a couple of days before full moon for better germination based on the research by the Koliskos which followed Steiner’s own recommendations for sowing and which has since been confirmed by Spiess (see Moon & Stars: Sidereal, below). In contrast a new moon is the appropriate time for vineyard cover crops to be ploughed in to the soil so that they decompose, because this is when moon force activity is concentrated underground and exerts an inward contraction. For this reason new moon is also a beneficial time to cut hay (it dries more easily), sow seeds for root (below-ground) crops or to transplant.

Bibliography

Monty Waldin, Biodynamic Wine (Infinite Ideas, Oxford).