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Letter to the Editor

Re: Do Lunar Phases Influence Plant Chemistry?

To the Editor,

Thank you for the excellent article of Ian B. Cole and M. J. Balick published in HerbalGram 85. This contribution opens interesting perspectives, both at the level of fundamental research and at the level of practical applications for obtaining improved raw material quality.

Since we started working on the field of tree chronobiology linked to lunar rhythms, it has been possible to observe significant relationships for different aspects of tree life and wood properties. Here is a short overview:

  • The germination and initial growth of some tropical trees show a decided rhythmic character. Speed of germination, percent of germination, average height, and maximum height after 4 months are systematically related to the timing of sowing in relation to the moon phase.1,2

  • The drying behavior (water loss/shrinkage) and the final density of wood systematically and coherently vary in function of the tree felling date, if analyzed in relation to the season and to the position of the moon.3,4 The observed fluctuations are yet more complex than mentioned in forestry traditions existing all over the world.

  • An interdisciplinary reworking of previously published, long-term tree-physiological research results (variations of tree diameters obtained by extensometry) has enabled researchers to consider an unexpected aspect: the synodic (time required for the moon to complete a full phase, i.e., usually 29.53 days) moon-rhythm at a daily level (gravimetric tide-rhythm) could be established for trees held under constant conditions (darkness).5

  • Data of trees measured in open conditions, reanalyzed recently with more sophisticated tools, brought spectacular confirmation of the role of lunar tides in tree physiology.6 In the meantime, it had been possible to detect the same type of fluctuations by measuring with a highsensitivity device the low-potential electric currents along the trees’ stems, depending on the physiological phase of the trees.7

This information, and more, is summarized in my extensive review of 88 scientific publications related to this topic, published recently in a book on botany.8

—Ernst Zürcher, Dr. sc. nat., Forest Engineer ETHZProfessor for Wood ScienceBern University of Applied Sciences, Architecture, Wood and Civil Engineering


  1. Zürcher E. Rhythmizitäten in der Keimung und im Initialwachstum einer tropischen Baumart. Rythmicités dans la germination et la croissance initiale d›une essence forestiere tropicale. Schweizerische Zeitschrift für Forstwesen. 1992; 143(12):951-966.

  2. Zürcher E. Lunar rhythms in forestry traditions - Lunar-correlated phenomena in tree biology and wood properties. Earth, Moon and Planets. 2001;85-86(13):463–478.

  3. Zürcher E, Mandallaz D. Lunar synodic rhythm and wood properties: traditions and reality. In: Quentin I, ed. L’arbre 2000 The Tree. Montréal: Montréal Botanic Garden; 2000:244-250.

  4. Zürcher E, Schlaepfer R, Conedera M, Giudici F. Looking for differences in wood properties as a function of the felling date: lunar phase-correlated variations in the drying behavior of Norway Spruce (Picea abies Karst.) and Sweet Chestnut (Castanea sativa Mill.). Trees. 2010;24:31-41.

  5. Zürcher E, Cantiani M-G, Sorbetti-Guerri F, Michel D. Tree stem diameters fluctuate with tide. Nature. 1998;392:665-666.

  6. Barlow, PW, Mikulecky M, Strestik J. Tree-stem diameter fluctuates with the lunar tides and perhaps with geomagnetic activity. Protoplasma (online): April 15, 2010.

  7. Holzknecht K, Zürcher E. Tree stems and tides – A new approach and elements of reflexion. Schweizerische Zeitschrift für Forstwesen. 2006;157(6):185-190.

  8. Zürcher E. Les Plantes et la Lune – Traditions et Phénomènes. In: Aux Origines des Plantes – Des plantes anciennes à la botanique du XXIè siècle. Hallé F., ed. Paris: Fayard; 2008:389–411.

Dear Editors,

Your cover article on Lunar Influence on Herbs in issue 85 consisted mainly of old superstitions and had no data or evidence on influence of the moon on herbs or any other plants.

Statements on effect of the moon on harvesting of wood products not only did not fit the title of the article but were outdated. Why do lumber companies around the world harvest non-stop through the seasons with no consideration of the moon—yet they have uniformity in quality of their products? Why do farmers with large acreage plant non-stop over several weeks when the weather and soil conditions are good? They do not have differences in harvest from different sections of the farm based on the date of agricultural work.

I worked for 3 months for the Forest Service testing germination of seed. For each test we had “common seed” germinating as controls. Had there been differences in germination under different signs of the moon it would have shown up in the tests to alert us to the errors in our results. Over 3 months there was no significant deviation in germination except for quality of the seed we were testing. No influence on germination of seed from the moon. No difference in germination when conditions of heat, moisture, light, fertility, etc, were constant. Those are the things that influence germination and growth of plants. Those are the things that give seasonal variation in quality from plants—not signs of the moon.

Most of the references listed in the article appeared to be based on hearsay, not on tests or reports of experiments.

Getting multiple references that are not scientific or valid does not add validity to an inaccurate supposition. The information in the article was worthless and misleading—not worth printing or reading.

—C. Dwayne Ogzewalla, PhDProfessor EmeritusUniversity of Cincinnati, College of Pharmacy

Authors’ Response:

We deeply appreciate the feedback from Dr. Ogzewalla on our brief review article. Our intention in preparing this article was to survey the peer-reviewed literature as well as folkloric beliefs as a prelude to our own studies of the variation in compounds found in a swamp palm used for thatch, and observe whether or not such variation could be documented over the lunar cycle. This intention was clearly stated in the article. Our first results, which we now are repeating, on a species of palm used for thatch, seem to validate the hypothesis that lunar cycle—as determined by evaluating samples made from the daily harvest of palm leaves during a six-week period—seems to have an impact on plant chemistry. But until this work is repeated, we cannot be certain of the variation found in this individual species.

As specialists in ethnomedical and ethnobotanical practices, the occurrence of similar beliefs in so many disparate parts of the world— in this case the effects of moon phase on composition and durability of a variety of products—is fascinating and in our judgment worth testing. We have learned long ago to not be immediately dismissive of traditional beliefs—but rather use the tools of modern science to help separate “fact” from what is purely speculative or a folkloric, perhaps animistic, explanation for a specific phenomenon. While Dr. Ogzewalla did not observe the influence of outside forces on his own seedling experiments, we know, for example, that in the field of conventional drug discovery and clinical evaluation, there are many trials that yield negative results while others yield positive results. And to take the specific case of mood-enhancing pharmaceutical drugs, the fact that there are only a few positive trials with small increases above placebo in some formulations (vs. more numerous negative trials) has been effectively used as a case for governmental approval of these individual therapies.

It is widely acknowledged that many factors—soil, moisture, cultivation practices, altitude and others—influence the chemistry of a botanical. Is it possible that there is a lunar influence on herbs? Can and should we test the traditional beliefs—often held by widely dispersed societies that have been observing their environments for millennia? Others may disagree, but we suspect that decades from now, this question will be viewed as having been worth studying at a variety of levels—e.g., variation in botanicals, timber, wine, food crops, etc.—and more conclusive results may even be available to the scientific and consumer communities to discuss and debate. We believe it is instructive to remember that not many decades ago, nutrition was dismissed as not being worth more than a relatively brief mention in a medical student’s training. How far we have come.

—Ian B. Cole Research Associate Montgomery Botanical Center

—Michael J. Balick, PhDVice President for Botanical ScienceDirector and Philecology Curator of the Institute of Economic BotanyNew York Botanical Garden