The Gardening By The Moon calendar relies on the earlier scholarship of Caren Catterall, whose work built on that of the late Louise Riotte, who wrote many entertaining and informative texts over her career (some of which are cited below).
Riotte based her work on the geocentric—or earth-centered—method of calculating zodiac positions, rather than the heliocentric—sun centered—method used by some other almanacs. At the beginning of Astrological Gardening, she explains her choice by relating the discoveries of Dr Clark Timmins, who had recently conducted a set of studies proving that tomatoes thrived better when planted and transplanted under Cancer than Leo:
Then something else came to Dr. Timmins’ attention. He observed that there had been similar tests reported that did not indicate results favorable to the moon-planting theory. As a scientist, he questioned why one set of experiments indicated a positive verification of moon-planting, and others did not. Upon checking the other texts, he found that the experimenters had not followed the geocentric system for determining the moon sign positions, but the heliocentric. When the times used in the other experiments were converted to the geocentric system, the dates chosen were found to be barren rather than fertile signs. Geocentric and heliocentric positions often vary by as much as four days. This is sufficient to place the moon in Cancer, for example, under the heliocentric system, and at the same time in Leo according to the geocentric system (Riotte 1989, pp 10-11).
Although planting by the phase and sign of the moon made an intrinsic sense to me—so many things in nature are connected in these intricate, esoteric webs, so many of them organized around lunar events—I’m also a person who appreciates scientific evidence and a good research project; when Wolf Hill bought the calendar, I was thrilled to begin a deep dive into the studies cited in Riotte’s books. She references researchers from centuries past through to the present day, such as Francis Bacon, who studied the moon’s effect on germination; Dr Harold Burr of Yale, who studied correlation of moon phase with tree growth; Dr Lily Kolisko of the Stuttgart Biological Institute, who studied the moon’s effects on not only the growth but also the flavor of vegetables.
This research project is very much ongoing and I will update this page as I learn more; I especially look forward to sharing the sources and studies wherever possible, and have been working to locate the studies Riotte refers to on publicly accessible internet archives. At time of writing, most of my time has been occupied with starting a new business and transferring Gardening by the Moon, so I haven’t gotten as far into this project as I would like. What I have seen, though, is both promising and thrilling—experiments on astrological gardening date back to the 1500s, making them some of the first scientific studies ever conducted!
Something else I’ve noted is that in many studies, the moon’s phase is shown to have an effect on plant and animal life even when the organisms being studied are in dark rooms, far away from any direct exposure to the moon. For me, this attests not only to the factual basis for these gardening technologies, but also to the unseen, spectacular power that animates all life and connects us all.
Of course, some people follow lunar planting for reasons far older than Western scientific evidence. Cultural knowledge, oral history, and local tradition have all passed it down from generation to generation for many centuries.
Planting by the signs in the United States goes back at least to the time of the first Scotch-Irish settlers in the ancient Appalachians mountains; many of their descendants interviewed for the Foxfire magazine cite the Bible—particularly Genesis 1:14 and Ecclesiastes 31:1-2—as their source. Louise Riotte herself learned about planting by the signs as a child from her father, a German immigrant to Kentucky, who presented it with the same straight-forward normalcy as the tasks of mulching and pruning. He in turn had learned it from his parents and grandparents during his own childhood in their Rhine valley vineyard.
Since time immemorial, many Indigenous nations have practiced their own traditions of lunar planting. The incredible food forests that once covered northeastern Turtle Island were built and maintained under the guidance of these synodic cycles.
I encourage anyone who’s interested in lunar planting to do some research into indigenous technologies and knowledges around it, especially where you live; in many cases, the land, the plants, and these systems of farming co-evolved, and it may be advantageous for you to incorporate techniques which are native to your area. I can present what I’ve learned here but I am certainly not an expert and I recommend learning from teachers and elders in your area if you can. Many of the indigenous people I’ve learned from are Haudenosaunee (the Six Nations Confederacy whose landbase spans upstate NY, southern Ontario, and southern Quebec) or are of other nations indigenous to the Eastern Woodlands.
I was lucky to see a Kanien’kehá:ka (Mohawk) Seedkeeper, elder Stephen Silverbear McComber, speak recently about how he began planting by the moon and how he first determined which phases were best for which activities by running a series of experiments. He knew that his people had traditionally planted, weeded, and harvested by the cycles of the moon, but the specific knowledge had been lost over the many generations of the residential school system. I was struck by the tragedy, of course, but also by the hope, the durable optimism of that act.
Rowen White is another Kanien’kehá:ka Seedkeeper who writes frequently on the power of generational memory, of intergenerational healing, and of building relationships with the plants who make up our world. She teaches a cycle of planting, germination, and transplanting based in the rhythms of the lunar month (I highly recommend her online seedsaving mentorship course!).
There are reasons to plant by the signs, whether you place your faith in science or tradition or something else entirely. For me personally, the amount of time I’m able to work outside is limited, so I want to know I’m using my time as effectively as I can, doing the most good for the plants and land in my care with my finite hours.
As with all things, there are people who disagree and scoff, and to them I quote a farmer I once worked for: “Anything that gets me out to weed is good for the garden.”