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Spring Home and Garden: Gardening by phases of the moon (part 2)

Lunar influences include light given off from the moon, gravitational and magnetic forces
PLANTING SEASON: As temperatures rise, greenthumbs are drawn outdoors, and always on the lookout for ways to increase the yield from their gardens.

Part one of this article was published on March 24.

Does gardening by phases of the moon work?

There are many publications and websites that extol the virtues of gardening by phases of the moon. But is there any proof of its effectiveness? What does science tell us?

Many have asked this question. In particular, four researchers and professors from Spain went to great lengths in 2020 to answer this in their review: What has been thought and taught on the lunar influence on plants in agriculture? Perspective from physics and biology. Their review explored over 100 textbooks, physics handbooks, research and other materials that spanned the years from 1923 to 2019 looking for scientific proof of relationships between phases of the moon and plant development. Some of the aspects explored relate to the moon while others relate to plants.

Lunar influences include light given off from the moon, gravitational and magnetic forces, and the effect the moon might have on other organisms that interact with plants. There are many factors that could influence how plants develop. These generally fall into two or three categories.

There are internal factors within the plant and external factors within the environment. Another category not really explored in any detail is the ways in which plants and their environments interact with each other. For instance, I do not recall any mention of how the gardener related to the plants – or the environment for that matter. But we will get to that later.

Examples of internal factors that could influence plant development are hormonal responses involved in growth, transport of nutrients, healing and responding to stresses. Examples of external factors in the environment are numerous and include the amount of sunlight, temperature, precipitation, wind, insect infestations, soil composition and chemicals (think fertilizers or pollution).

These authors found almost no scientific evidence to support any claims that the moon influences growth of plants in any significant way. Using equations based on laws of physics they calculated that gravitational and magnetic forces from the moon would be infinitesimal in terms of exerting any force on movement of sap in plants.

Similarly, using calculations relating to illuminance, moon radiation, photoperiod and phases of the moon, they determined the light of the moon would not be strong enough in most instances to have an impact, although there was a possibility that flowering may be delayed slightly in some plants.

In all these studies, there were fewer than a handful of instances where the moon was considered to have affected plants. One found that some sphagnum mosses had a decrease in their rate of growth near the full moon and had accelerated growth around the new moon. Another found that the phase of the moon at the time of sowing seeds may influence germination.

Some other research suggested a possibility that flowering may be delayed slightly in some plants, although it did not specify what those plants were. There was also a suggestion that moonlight could influence insect behaviour, which could indirectly affect plants. For instance, the light of the full moon can assist some insects to see glistening sap on unpollinated cones, thereby increasing pollination rates of the cones.

Of course, there were some limiting aspects of this study. As the authors suggest, it would be valuable to consider what influences the moon may have on other organisms – including mammals – that could indirectly affect plants. However, they could not find any conclusive research that looked into this.  

It was interesting to me that one of the main reasons the authors gave for doing this review was because of their concern about pseudoscience making its way into agricultural practices. They went to great pains to look for scientific proof because farmers and gardeners today continue to use reference books that promote agricultural traditions that pay homage to lunar cycles without any scientific proof to back them up. However, they did acknowledge that, despite the lack of science, many of these practices foster cultural and Indigenous well-being, promote sustainability, biodiversity and support “a harmonious and sustainable coexistence with their natural environments.”

So, what are the takeaways from this?

There was no hard scientific evidence that the moon exerted any measurable influence on plants. But perhaps there are immeasurable influences at play that cannot be quantified with mathematical equations. Planning crops and sowing seeds according to lunar cycles has been part of agricultural knowledge since beyond antiquity.

The Mayans followed the cycles of the sun and other planets for thousands of years and their traditions continue to this day. And there are agricultural traditions that have been preserved in other parts of the world as well. Does this mean that, for millennia, farmers have simply been influenced by superstition, mysticism or old wives’ tales? 

Then again, old wives’ tales are based on the knowledge of our repeated experiences, so perhaps they should not be discounted too quickly. The editors of Rodale’s Ultimate Encyclopedia of Organic Gardening observe that, while we may think it is foolish, there are enough “first-rate gardeners” who do follow lunar phases to make us pause before dismissing it out of hand. And also, following the movement of celestial bodies helps us to align with “natural rhythms in the universe.”

Perhaps getting in tune with some of these natural rhythms may be a way to feel as though we are more connected with an ecosystem that seems to have lost some of the cyclical stability and weather patterns we have taken for granted. Following the lunar phases may be a way to tap into a more gentle kind of wisdom that at least will do no further harm - and you may find that it is pretty enjoyable.

And while there may not be concrete proof that gardening by the moon increases yields, there is no harm done either. In medicine there is something called the placebo effect in which the act of doing something can have a positive effect on a person’s well-being regardless of whether the action has any measurable benefit on, say, blood chemistry or pain receptors – in other words, any scientific benefit.

An article by Harvard Health Publishing suggests that part of the power of the placebo effect is in the ritual of treatment. And that the process of going to the doctor and having tests done and getting a prescription and taking a pill even though there is no medication in it is why it works.

This brings us back to my comment that there was no mention of the gardener when talking about possible factors in the environment that might influence how a plant develops. Perhaps planting by the phases of the moon accords benefit to our gardens in a similar way as the placebo effect.

Perhaps it is by following a ritual, or tradition of respecting the cyclical nature of our world that we create a space where plants can prosper. Perhaps synonyms for “placebo” could be “belief” or even “faith.”

And perhaps we are correct in believing that we are giving our plants -and maybe even our planet – the strongest chance for success when following the natural rhythms of our ecosystem.

Here is an anecdotal story about the effectiveness of gardening by the phases of the moon. As Valerie Lane, one of the garden club members wrote, “I have followed the Llewellyn’s Witches Calendar for many years with good success. As I get older I have had to follow it when I can, as my back dictates what gets planted when rather than the phases of the moon. I started planting this way years ago when one of my older Italian neighbours told me if I harvested my garlic on the full moon it would last right through to the following scape season. And it does.”

Susan Onlock is a Powell River Garden Club member. Contact the club at [email protected] to arrange a visit and have all questions answered, plus get some valuable advice on how to get started.