Bark at the moon

Q: My local newspaper runs a weekly column about planting flower and vegetable gardens by the phases of the moon and the signs of the zodiac. For the life of me, I can't understand how either could have any bearing on a seed planted in the ground....

A: Your question is a good one that addresses an issue all too rarely questioned when people hear unusual claims: "What is the mechanism?" Claimants and mystery-mongers are usually too busy promoting the end-result of the claims (e.g., "I can read people's minds!" or "This woman can detect water with a dowsing rod!") to address the fundamental question of how exactly these phenomena supposedly happen.

Astrologers in particular have repeatedly failed to explain how the exact position of planets and celestial bodies could have any possible effect on a newborn. Why would a planet here or there somehow decide which personality traits of the twelve sun signs a newborn would eventually exhibit?

The zodiac question is all the more dubious when applied to plants.

Jackie French, an avid gardener and author of several gardening books, had the same question and looked into this phenomenon. Upon first encountering the claim, she stated that "moon planting seemed like a load of codswollop." (French lives in Australia, where colorful phrases like "a load of codswollop" are much more common and effective than stateside.) French made some initial investigations using bean seeds, all of which showed no moon effect at all. That's where the matter stood for many years. Yet French kept hearing about the benefits of moon planting from long-time gardeners who seemed certain of the moon's effects. French decided, codswollop or no, to try again. The results were still negative, but one morning at daybreak it dawned on her (as luck and metaphor would have it), that perhaps there was an effect, but it had nothing to do with the moon's phases.

French described her analysis: "Let's look at a possible scenario. Gardener 1 is a moon planter; Gardener 2 is not. Both gardeners wait till spring to plant their beans.... But come the first warm spell, Gardener 2 succumbs to one of the great spring urges and plants the beans at the first hint that spring has arrived. Gardener 1, on the other hand, waits till the next good moon planting time before planting the seeds. Early warm spells are usually followed by another cold one ... and seeds planted too early may rot. Even if it doesn't, plants that suffer any setback when they are young usually don't do as well as plants that have flourished right from the start. So, counter-intuitively, beans that are planted later in spring will probably do better than beans planted too early. The result: Gardener 1's moon-planted beans produce sturdier plants and crop earlier.... It's this tendency to slightly later spring planting and perhaps slightly earlier autumn planting, that I suspect is the reason so many gardeners will swear that they see an effect."

[ILLUSTRATION OMITTED]

Sometimes when investigating the paranormal we find that the effect is real enough, but the causes are misattributed; this is an example of the common logical fallacy of post hoc ergo propter hoc, after this, therefore because of it. The answer lies not in the stars, but in botany, human nature, and logic.

Reference

French, Jackie. 2005. Why moon planting works. The Skeptic (Australia), Summer 25(4): 20-22.

Benjamin Radford is a writer and investigator with the Committee for Skeptical Inquiry. His Web site is at www.RadfordBooks.com.

COPYRIGHT 2008 Committee for the Scientific Investigation of Claims of the Paranormal
COPYRIGHT 2008 Gale, Cengage Learning