# Gardening and the lunar cycle **URL:** \ **Category:** Factual Questions\ **Created:** [February 9, 2009, 4:04am UTC](https://boards.straightdope.com/t/gardening-and-the-lunar-cycle/485006 "2009-02-09T04:04:00Z")\ **Posts on this page:** 18\ **Page:** 1
**Author:** ![Helen\_s\_Eidolon](https://avatars.discourse-cdn.com/v4/letter/h/8edcca/32.png) [@Helen\_s\_Eidolon](https://boards.straightdope.com/u/Helen_s_Eidolon)\ **Post date:** [February 9, 2009, 4:04am UTC](https://boards.straightdope.com/t/gardening-and-the-lunar-cycle/485006/1 "2009-02-09T04:04:00Z")
My roommate’s Italian grandfather imparted to her the secrets of good gardening - what phases of the moon are appropriate for what gardening acts. She thinks the explanation was something about the moon’s effect on the moisture of the soil. I, as a good Doper, am pretty skeptical, and would like to show my roommate that my skepticism is justified. Unfortunately, given the amount of crazy mystical moon-mother websites out there, I’m having trouble coming up with anything on Google. I’ve found some good stuff on how human bodies aren’t affected by the moon, but nothing about plants. ---
**Author:** ![Zsofia](https://avatars.discourse-cdn.com/v4/letter/z/7bcc69/32.png) [@Zsofia](https://boards.straightdope.com/u/Zsofia)\ **Post date:** [February 9, 2009, 2:22pm UTC](https://boards.straightdope.com/t/gardening-and-the-lunar-cycle/485006/2 "2009-02-09T14:22:33Z")
My dad, who has a degree in electrical engineering and has run his own business profitably for decades, honestly believes that whether you have “extra” dirt or “not enough” dirt when you dig a hole depends on whether the moon is waxing or waning. He cannot be argued out of it. It’s some sort of folk tradition, and I suppose it’s true that you can’t reason somebody out of a position they didn’t reason themselves into. (I forget what phase of the moon it was when we buried my dog last week, but we were laughing because if Dad had been there instead of at the doctor’s he would have told us we’d have leftover dirt, like, duh, there’s a wicker box with a dead dog in it that we added to the hole.) ---
**Author:** ![Squink](https://avatars.discourse-cdn.com/v4/letter/s/b5e925/32.png) [@Squink](https://boards.straightdope.com/u/Squink)\ **Post date:** [February 9, 2009, 3:01pm UTC](https://boards.straightdope.com/t/gardening-and-the-lunar-cycle/485006/3 "2009-02-09T15:01:05Z")
[Plants and Light](http://urbanext.illinois.edu/hortihints/0012b.html) > [@](#): > > Some seeds are also light sensitive. Germination is controlled by the reaction in the phytochrome pigment. Many lettuce varieties must have light to germinate. Lettuce is packaged and distributed in foil packets to prevent sprouting before planting. Most weed seeds are in this category. Have you noticed how every time you till the soil more weeds shoot up? Weed seeds lie dormant in the soil for years waiting for you to stir up the soil so they get enough light to germinate. The phytochrome systems, which mediate a plants responses to light, are sensitive to _red_ light, not a color the moon is noted for, except during eclipses. The phytochromes are also [not very sensitive to light:](http://science.jrank.org/pages/5305/Plant-Pigment-Phytochrome.html) > [@](#): > > There are three types of phytochrome reactions which control plant growth and development. The “very low fluence responses” require very little light, about one second of sunlight; the “low fluence responses” require an intermediate amount of light, about one sound of sunlight; and the “high irradiance responses” require prolonged irradiation, many minutes to many hours of sunlight. So unless there’s an undiscovered and very sensitive phytochrome system, plants are not affected by moonlight. ---
**Author:** ![AskNott](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/asknott/32/5790_2.png) [@AskNott](https://boards.straightdope.com/u/AskNott)\ **Post date:** [February 9, 2009, 3:26pm UTC](https://boards.straightdope.com/t/gardening-and-the-lunar-cycle/485006/4 "2009-02-09T15:26:22Z")
The folklore goes beyond plants. I worked with a farmer’s son who said he was taught that fence posts placed under the wrong side of the moon would be frost-heaved out in the next winter. His dad showed him ragged fences on a neighbor’s land to “prove” it.:dubious: ---
**Author:** ![Sapo](https://avatars.discourse-cdn.com/v4/letter/s/ec9cab/32.png) [@Sapo](https://boards.straightdope.com/u/Sapo)\ **Post date:** [February 9, 2009, 3:40pm UTC](https://boards.straightdope.com/t/gardening-and-the-lunar-cycle/485006/5 "2009-02-09T15:40:23Z")
I was just about to start a thread very much along these lines. In the spirit of sharing nutteries we have heard, my FIL insists I should always plant on Fridays. He hasn’t a good explanation why, but he insists this is vital stuff. The way I have heard the moon phase thing explained, is that as with tides, water table levels are influenced by the moon. This makes some moons more favorable to plantings/prunings than others. ---
**Author:** ![psycat90](https://avatars.discourse-cdn.com/v4/letter/p/7ea924/32.png) [@psycat90](https://boards.straightdope.com/u/psycat90)\ **Post date:** [February 9, 2009, 5:44pm UTC](https://boards.straightdope.com/t/gardening-and-the-lunar-cycle/485006/6 "2009-02-09T17:44:29Z")
A planting and sowing calendar based on moon phases, etc. is a large part of biodynamic farming. Gaining popularity among many vineyard owners in this area, including one of the largest I know of - [Benzinger](http://www.benziger.com/farming/). Check out the [Biodynamic Farming and Gardening Association](http://www.biodynamics.com/) and [Demeter](http://www.demeter-usa.org/) for more info. ---
**Author:** ![Helen\_s\_Eidolon](https://avatars.discourse-cdn.com/v4/letter/h/8edcca/32.png) [@Helen\_s\_Eidolon](https://boards.straightdope.com/u/Helen_s_Eidolon)\ **Post date:** [February 9, 2009, 9:50pm UTC](https://boards.straightdope.com/t/gardening-and-the-lunar-cycle/485006/7 "2009-02-09T21:50:23Z")
Interesting, **psycat**. Thanks for the links. I can’t seem to find anything on them that indicates they’re based in scientific principles. I was half-joking that I’m convinced if I look into some Roman agricultural manuals, I’ll find the same advice. ---
**Author:** ![Chronos](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chronos/32/134_2.png) [@Chronos](https://boards.straightdope.com/u/Chronos)\ **Post date:** [February 9, 2009, 10:12pm UTC](https://boards.straightdope.com/t/gardening-and-the-lunar-cycle/485006/8 "2009-02-09T22:12:17Z")
Of course, even if it doesn’t affect the garden directly, it might affect the gardener. Timing things by the Moon might be because you’ll need to work late to do certain tasks, and the moon gives you light to see by for doing them. And planting on Fridays might originally have been because there’s something you’re supposed to do two days after planting, and you want to have time to do it on the weekend. ---
**Author:** ![Karyn](https://avatars.discourse-cdn.com/v4/letter/k/fbc32d/32.png) [@Karyn](https://boards.straightdope.com/u/Karyn)\ **Post date:** [February 9, 2009, 10:16pm UTC](https://boards.straightdope.com/t/gardening-and-the-lunar-cycle/485006/9 "2009-02-09T22:16:37Z")
Most pot growers that I’ve known swear that it’s best to plant at the new moon and stop watering a week before the full harvest moon to get the stickiest buds. Maybe there’s something to it but they’re all full of hippie woo anyway so I’m not convinced. ---
**Author:** ![Dr.Drake](https://avatars.discourse-cdn.com/v4/letter/d/ad7895/32.png) [@Dr.Drake](https://boards.straightdope.com/u/Dr.Drake)\ **Post date:** [February 9, 2009, 10:19pm UTC](https://boards.straightdope.com/t/gardening-and-the-lunar-cycle/485006/10 "2009-02-09T22:19:44Z")
The relationship is 100% magical thinking. There’s ton of information about it in folklore sources. If you’re dealing with a folk belief that is tied into someone’s identity, you’re not going to have much luck changing their mind by appealing to science, especially when confirmation bias is so easy to apply. People also have a regrettable tendency to justify their folk beliefs with shoddy science. Most plants are planted with the waxing moon because growing moon = growing plants. A few plants come from opposite land, and some of them are to be planted at the dark of the moon, but that has more to do with the nature of the plant than of the moon. ---
**Author:** ![psycat90](https://avatars.discourse-cdn.com/v4/letter/p/7ea924/32.png) [@psycat90](https://boards.straightdope.com/u/psycat90)\ **Post date:** [February 9, 2009, 11:18pm UTC](https://boards.straightdope.com/t/gardening-and-the-lunar-cycle/485006/11 "2009-02-09T23:18:12Z")
> [@Helen\_s\_Eidolon](#): > > Interesting, **psycat**. Thanks for the links. I can’t seem to find anything on them that indicates they’re based in scientific principles. > > I was half-joking that I’m convinced if I look into some Roman agricultural manuals, I’ll find the same advice. Oh yea, Science. 😛 I was just giving some examples of their use. Personally, I’d say no, there is no scientific basis, or very little scientific basis. ---
**Author:** ![BleizDu](https://avatars.discourse-cdn.com/v4/letter/b/9dc877/32.png) [@BleizDu](https://boards.straightdope.com/u/BleizDu)\ **Post date:** [August 7, 2010, 9:31am UTC](https://boards.straightdope.com/t/gardening-and-the-lunar-cycle/485006/12 "2010-08-07T09:31:15Z")
Resurecting this to ask if people know of studies that have been done on the hypothetical effect of moon gardening? I only found some stuff there (from 2006): [http://curious.astro.cornell.edu/question.php?number=701](http://curious.astro.cornell.edu/question.php?number=701) > [@](#): > > I could not find any extensive scientific studies conducted to test the proposed benefits of lunar gardening. There was a study done by the Agricultural Research Service in Iowa where they found a link between weed germination and exposure to light. They determined that tilling the soil (i.e. bringing weeds to the surface) was best done at night by a new moon (when there was as little light as possible). Tilling in the dark led to less weed seed germination and thus to fewer weeds in the garden. We often hang out with folks who are deep into woo and they’re often all about moon gardening. We’re of the mind it may help folks to remember to plant or sow this or that and not to forget to take care of their garden, so these people might see better results than if they were following a more flexible plan. But I would be curious to see if it has been ever tested, like, do beginner gardeners work better following the moon than not, something like that. But any studies or research on the possible effect of moon on gardening would be good. ---
**Author:** ![qpw3141](https://avatars.discourse-cdn.com/v4/letter/q/6bbea6/32.png) [@qpw3141](https://boards.straightdope.com/u/qpw3141)\ **Post date:** [August 7, 2010, 9:42am UTC](https://boards.straightdope.com/t/gardening-and-the-lunar-cycle/485006/13 "2010-08-07T09:42:03Z")
They carried out an experiment on exactly this at Kew Gardens and found that the moon had no effect whatsoever. ---
**Author:** ![aruvqan](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/aruvqan/32/2891_2.png) [@aruvqan](https://boards.straightdope.com/u/aruvqan)\ **Post date:** [August 7, 2010, 10:16am UTC](https://boards.straightdope.com/t/gardening-and-the-lunar-cycle/485006/14 "2010-08-07T10:16:15Z")
> [@Helen\_s\_Eidolon](#): > > Interesting, **psycat**. Thanks for the links. I can’t seem to find anything on them that indicates they’re based in scientific principles. > > I was half-joking that I’m convinced if I look into some Roman agricultural manuals, I’ll find the same advice. OK, here, [De Agricultura](http://penelope.uchicago.edu/Thayer/E/Roman/Texts/Cato/De_Agricultura/home.html) by Cato Columella’s [Res Rustica](http://penelope.uchicago.edu/Thayer/E/Roman/Texts/Columella/home.html) for a different viewpoint 😃 ---
**Author:** ![Francis\_Vaughan](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/francis_vaughan/32/3093_2.png) [@Francis\_Vaughan](https://boards.straightdope.com/u/Francis_Vaughan)\ **Post date:** [August 7, 2010, 11:53am UTC](https://boards.straightdope.com/t/gardening-and-the-lunar-cycle/485006/15 "2010-08-07T11:53:22Z")
Friday planting raises a heap of obvious questions. Mostly about how the plant knows its Friday, and what its opinion of the Julian Calendar is. Of course Friday has always been a bit mystical in the Judaic mythos. The moon comes into play in about every tradition you can think of. The Sun has a relative magnitude of -26.8 and the Moon of -12.6, so a difference of 14.2, which is a ratio of pretty close to half a million times. So, one second of full sunlight is equalled by 133 hours of full moonlight. Considering there are only 168 hours in a week, of which roughly half are daylight, it seems pretty difficult to get any meaningful correlation to the moon’s cycle with anything that needs a second or more of sunlight equivalent. However a few things are sort of interesting. Despite what your eyes suggest, the moon is actually inherently reddish. It has nearly twice the albedo at far red wavelengths as at blue, and indeed seems to have an almost straight line albedo spectrum. [http://esapub.esrin.esa.it/eoq/eoq52/dob52.htm](http://esapub.esrin.esa.it/eoq/eoq52/dob52.htm) Your eyes are not spectrometers, and just because you see something as bluish does not mean there isn’t a lot of long wavelength light still present. It seems that the actual spectra of light is important if the phytochromes are active. The plants remember the last thing they saw. [http://www.nature.com/embor/journal/v3/n11/full/embor036.html](http://www.nature.com/embor/journal/v3/n11/full/embor036.html) Seeing red or far red determines whether they stay dormant. Moonlight contains more far red then red, by proportion, than sunlight. I still think it is bunkum. The actual flux of light is minimal, and nobody explains what happens when the sun comes up. But I was amused to see what turned up. ---
**Author:** ![BleizDu](https://avatars.discourse-cdn.com/v4/letter/b/9dc877/32.png) [@BleizDu](https://boards.straightdope.com/u/BleizDu)\ **Post date:** [August 10, 2010, 2:47pm UTC](https://boards.straightdope.com/t/gardening-and-the-lunar-cycle/485006/16 "2010-08-10T14:47:41Z")
> [@Francis\_Vaughan](#): > > The Sun has a relative magnitude of -26.8 and the Moon of -12.6, so a difference of 14.2, which is a ratio of pretty close to half a million times. So, one second of full sunlight is equalled by 133 hours of full moonlight. Considering there are only 168 hours in a week, of which roughly half are daylight, it seems pretty difficult to get any meaningful correlation to the moon’s cycle with anything that needs a second or more of sunlight equivalent. > > […] > > It seems that the actual spectra of light is important if the phytochromes are active. The plants remember the last thing they saw. [http://www.nature.com/embor/journal/v3/n11/full/embor036.html](http://www.nature.com/embor/journal/v3/n11/full/embor036.html) Seeing red or far red determines whether they stay dormant. Moonlight contains more far red then red, by proportion, than sunlight. Yes thanks, it was indeed really interesting! ---
**Author:** ![dracoi](https://avatars.discourse-cdn.com/v4/letter/d/90db22/32.png) [@dracoi](https://boards.straightdope.com/u/dracoi)\ **Post date:** [August 10, 2010, 7:19pm UTC](https://boards.straightdope.com/t/gardening-and-the-lunar-cycle/485006/17 "2010-08-10T19:19:32Z")
I can say, from experience, that Italian grandfathers have a reliability index somewhere below the National Enquirer when it comes to these sorts of things. My Italian grandfather also assured me that pointing at vegetables with a straight finger would ensure that they’d turn diseased and fall off the plant. ---
**Author:** ![constanze](https://avatars.discourse-cdn.com/v4/letter/c/f9ae1b/32.png) [@constanze](https://boards.straightdope.com/u/constanze)\ **Post date:** [August 11, 2010, 1:05pm UTC](https://boards.straightdope.com/t/gardening-and-the-lunar-cycle/485006/18 "2010-08-11T13:05:54Z")
Because the biologic-dynamic people strongly believe in the influence of star signs on growing of plants\*, Maria Thun has done 20 years of experimentation with the lunar cycle. She claims, with photos, that the effect of planting root veggies like carrots in the wrong and right sign are very visible (given that moon travels in a couple of days through the signs, it’s not a huge weather difference). I don’t know if any independt (blind study or by a non-believer) has ever been done, or whether any neutral scientist has looked at the evidence. The believers use this as proof of their claim. Either Thun is deluded/ faithful and using normal aberrations as proof; the lunar cycle does affect plant growth; or the belief of the gardener is strong enough to influence plants. 😉 \*Note: this is not about gardening in the light of the moon. Instead, each of the 12 signs of the Zodiac has a quality - earth, water, fire, air - associated with it. As the moon moves through the signs (using the actual astronomic tables!) - these qualities, together with the moon waxing or waning, are believed to influence the plants.