Does a Void of Course Moon Make a Difference for the Plant Kingdom?

By Hugh J. Courtney

In a biodynamic planting calendar, when the moon exits one constellation and enters another, you will usually see indicated a brief “blackout” period of at least an hour and for some calendars a period of as long as four hours as is the case with the Celestial Planting Calendar published by a Canadian team at What is the reason for this “blackout period?” In the Moon’s journey or transit through each constellation of the zodiac, there comes a point when it makes its last major aspect (see sidebar) with another member of the solar system. Between that moment and the moment that the Moon makes its entrance or ingress into the next constellation, the Moon is said to be “void of course,” which is understood as a situation where the Moon’s influence is nullified in its travels or “Void of Course.”

What may not be realized is that the insertion of blackout periods in a biodynamic calendar is an attempt to take into account the ancient astrological concept of the void of course Moon. However, what is not taken into account by those preparing a calendar is that the exact length of the period of time may vary from one minute to as long as a full day or more. Because of the difficulty of indicating these varying periods of time, it has proven to be more convenient to select a uniform, but arbitrary, length of time to indicate that one should not be working with soil or plants when the Moon exits one constellation and enters another. However, this artifice of convenience can have the effect of reducing the time that one can use to work with plants when the V/C Moon period is relatively brief. On the other hand, by failing to note with exactitude a long period of time when the Moon may be ineffective or ‘void,’ the grower may be working the soil or sowing seed without the full support of the cosmos via the Moon. This could result in introducing less desirable effects into the growing situation.

My personal theory is that a V/C Moon period ultimately will be found to have as negative an impact when working with plants as has been observed when an occultation, eclipse, or nodal point is involved. How might this be determined? One possible way might involve observing germination of particular seeds and subsequent performance of plants which are started both before and during a V/C Moon period.

Anyone interested in contributing to a solution of this problem is invited to use the V/C Moon information in the May and June 2019 calendar pages at the bottom of the article, to see if there is any difference in germination or plant performance for seeds started a few hours before a V/C Moon period versus seeds started well after such a period has commenced but also well before the Moon’s ingress into the next constellation. For ROOT periods, radish seed would be the choice; for FRUIT periods, bean seed might be a good choice; for LEAF periods lettuce seed could work; for FLOWER periods, any flower seed that normally germinates quickly (i.e. marigold) could be used. If the grower should notice any differences in germination percentages, or later on, any differences in growth and crop production so far as seeds planted at the different times, this would be worth noting.

Anyone choosing to address this question is asked to report their findings to the author at Earth Legacy Agriculture, LLC using e-mail address <> or directly to



The major aspects as though viewed from the earth are defined as follows:

☌ – conjunction = when two members (generally referred to as planets even when sun and moon might be involved) of the solar system are in the same degree of celestial longitude resulting in an aspect of 0 degrees between the two bodies.

⚹ – sextile = when two planets have an aspect of 60 degrees between them.

□ – square = when two planets have an aspect between them of 90 degrees.

△ – trine = when two members of the solar system relate to each other by an aspect of 120 degrees.

☍ = opposition = when two planetary bodies are directly opposite each other with an aspect of 180 degrees.

There are a number of other aspects taken into account in astrology calculations such as a quintile (72 degrees), or a sesquiquadrate (45degrees), or a semi-sextile (30 degrees), etc., but these minor aspects are not taken into account in determining a void of course Moon situation.


Void-of-course Moon for May & June 2019
(all times of ingress to the nearest hour in EDT)

The basic object will be to make a first planting before the V of C period and a second planting during the V of C period. Ideally at approximately the same time of day for both plantings. Pictures of your results would be very much appreciated.

May 3 – Moon conjunct Mercury at 4:17 AMthen Void until ingress into Aries at 6 PM – Plant lettuce seed on afternoon of May 2 and again on afternoon of May 3

May 5 – Moon trine Pluto 11:10 AMthenVoid until ingress into Taurus 12 PM (Noon)–Very narrow window – Plant bean seed on morning of May 4 (11:15 to 11:30) and again on morning of May 5 (11:15 to 11:30)

May 7 – Moon conjunct Mars 7:50 PM then Void until ingress into Gemini May 8 at 5 AM– Plant radish seed during evening(around 8:00 to 8:30 PM) of May 6 and again during evening(around 8:00 to 8:30 PM) of May 7

May 9 – Moon square Venus 10:06 PM thenVoid until ingress into Cancer May 10 at 6 AM– Relatively narrow window at inconvenient time– Plant marigold seed on very late evening of May 8 and again on very late evening (after 10:30 PM) of May 9

May 10 – Moon square Mercury 11:33 PM then Void until ingress into Leo May 11 at 4 PM– Plant lettuce seed on early afternoon of May 10 and again on early afternoon of May 11

May 14 – Moon square Jupiter 2:32 AM then Void until ingress into Virgo at 5 AM Extremely narrow window at very inconvenient time – Fanatics can Plant bean seed on morning of May 4 and again on morning of May 5 (between 2:32 and 5 AM)

May 17 – Moon opposite Uranus 00:03 AM thenVoid until ingress into Libra at 11 AM– Plant radish seed on morning of May 16 and again on morning of May 17 (around 9:00 to 10:30 AM both days) May 18 – Moon opposite Mercury 10:26 AM then Void until ingress

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