The idea that the Moon affects plant growth is an old one that is believed for many moons. It can be found in the folklore of ancient societies ranging from the Celts in Britain to the Maoris in New Zealand. Roman historian, Pliny the Elder, in his History of Nature, Book 18, gives much advice on planting by the moon phases. Today, it is still a rural tradition and in most countries you can buy moon gardening calendars.
The lunar experts suggest that you pick fruit at the full moon for the market as it will weigh more and pick at the new moon for personal consumption because the fruit stores better. Seeds also germinate faster when planted under the right phase of the moon.
A picture was posted recently in a Facebook Group showing a Planting by the Moon calendar on sale. I made a comment about being surprised people still believe in such things. That was a big mistake. Dozens of people jumped on me for not being a believer. How dare I say anything derogatory about what granny believed. Not one person came to my defense. The belief in planting by moon phases is still very common.
What is Planting by the Moon?
The Garden Media Group says that gardening by the moon is growing in interest again and is “more than just a phase”.
The main idea is that moon cycles affect plant growth and moisture in soil, in the same way as their gravitational pull causes tides to rise and fall. Seeds absorb more water during a full moon and therefore germinate better and grow stronger. Different time periods during the phases of the moon are better for planting specific crops.
A variety of sources publish annual planting calendars that will guide you to plant at the right time. This simple “Planting with the Moon” chart from Amazon is a great tool for this (this is an affiliate link).
Moon Gardening Calendar
The four main stages of the moon cycle are the new moon, waxing moon, full moon, and waning moon. The new moon is not visible because the earth completely blocks the sun light from hitting the moon’s surface. The waxing moon is crescent-shaped and is slowly getting bigger. The full moon is fully round and very bright which is then followed by the waning moon which is also crescent-shaped but getting smaller each day.
New Moon Gardening Guide
Moisture in soil is high and moon light is increasing making this a great time to plant. Seeds germinate easier and the extra light makes plants grow faster. It is an especially good time for plants that make seeds outside of the fruit, like lettuce, cabbage or spinach.
Waxing Moon Gardening Guide
Moisture levels are dropping but light continues to increase which helps plants grow foliage. The best time for planting is 3 days before the full moon and is most suitable for plants that have seeds inside their fruits, such as peppers, tomatoes, beans and squash.
Full Moon Gardening Guide
Moisture in soil is high again which helps plants, but the light is slowly decreasing, slowing growth. This is the perfect time to plant root vegetables like carrots, potatoes, rutabagas and beets, and to plant bulbs and perennials.
Waning Moon Gardening Guide
In this final moon phase the gravitational pull is low resulting in low water levels. Moon light is also low so the garden is resting and it’s a poor time to plant seeds. Focus instead on other gardening tasks like transplanting, fertilizing and pruning. Mowing the lawn at this time slows down its growth so you don’t have to mow as often.
Do These Guides Make Sense?
Why would seed from plants who make seeds inside a fruit and outside a fruit need different levels of moisture in the soil?
If moon light helps seedlings grow, why would you not plant everything at a full moon and just water a bit more?
If these moisture levels are of value, why would you plant transplants when moisture is at the lowest level?
Planting With the Moon – The Biological Clock
Mammals, including humans, have an internal timing mechanism called the biological clock which controls circadian rhythms on physiology, biochemistry and molecular events. We all know how screwed up our system gets when we fly across time zones. It has now been shown that plants do have a internal circadian rhythm.
The fact that they have a biological clock is not proof that changes in moon light affects plant growth.
I recently visited the Organic Conference in Guelph Ontario and looked at some Moon Calendar Books. It said, “plant beans on June 2, but don’t garden after 11:30. In the UK and Ireland, add a week”.
So in the UK, which is mostly zone 8, you should plant beans a week later than here in my zone 5 garden! And, you better not sleep in or you’ll run out of time.
The Moons Gravitational Pull
Isaac Newton’s laws of gravity explains that tides exist because the water in the oceans is being pulled by the moon’s gravity. Both the moon and sun pull on earth but since the moon is so much closer it has a greater effect than the much larger sun. Our oceans are affected the most when the moon and sun pull from opposite sides of the earth (full moon), or when they pull from the same side, resulting in higher tides (new moon).
If the moon can pull water in the ocean to cause tides, surely it also affects the water in plants and in soil. It is claimed that at the new and full moon more water is pulled to the surface of the soil which has the effect of speeding up the germination process. I found this statement on line, “a lunar gardening calendar that combines the best moon phase and sign together will help you achieve optimum results”, and it comes as no surprise that the website that makes his claim also sells lunar calendars.
Let’s return back to earth and look at the facts. The moon definitely affects ocean tides and produces waves. It also affects everything else on earth, but, and it is a big but, the effect on most things is so small we can’t see it and in many cases can’t even measure it. We don’t see the tides on small lakes because wind and currents from incoming rivers have a much greater effect than gravity from the moon or sun. On Lake Superior, which is the third-largest freshwater lake on the planet, the tidal influence is only two centimeters.
I could find no scientific evidence to support the idea that water levels are raised in soil during different phases of the moon nor is there evidence that the moon or sun affects the water level inside plants.
Claimed Research
A lot of the material on the internet refers to a 10 year study by Dr. Frank Brown, of Northwestern University. He found that in lab studies, plants absorbed more water during the full moon.
None of the dozen or more sites that refer to this work provided a reference. I have seen this before with other topics. People like to quote scientific studies to validate their belief without ever looking at the work. Dr. Brown did study the moon’s effect on animals, so the plant study may exist. If you find it, let me know.
The Science of Moon Gardening
There is scientific evidence that moon light does affect plants. The extra light can affect plants directly, and insects feeding on plants are also affected. But these effects don’t correlate with phases of the moon the way that is claimed by people gardening by the moon.
Lunar cycles do affect certain species, including some herbivorous insects which are dependent on moonlight for feeding. During the full moon, such insects feed more heavily and affected plant populations retaliate by altering the digestibility of their tissues.
The moon reflects sunlight at a very low intensity, which is negligible even at its peak and far below the level of photosynthetically active radiation (PAR) required to support photosynthetic growth of organisms on the ocean or land surface. The only plants that use moon light for photosynthesis are certain types of phytoplankton which are not normally found in gardens.
Here is what one review of the scientific literature said, “We found that there is no reliable, science-based evidence for any relationship between lunar phases and plant physiology in any plant–science related textbooks or peer-reviewed journal articles justifying agricultural practices conditioned by the Moon. Nor does evidence from the field of physics support a causal relationship between lunar forces and plant responses. Therefore, popular agricultural practices that are tied to lunar phases have no scientific backing.”
A newer study looked at the effect of full moonlight on plant cell biology and found that “despite the low-intensity light emitted by the moon, it is an important environmental factor perceived by plants as a signal, leading to alteration in cellular activities and changes in epigenetics”. Exposure of mustard seedlings to full moon light for 3 consecutive nights resulted in more growth than exposure to darkness. The seedlings were not grown to maturity to see if the light actually affect yield.
Biodynamic Agriculture
“In Biodynamic agriculture the entire farm, the surrounding terrain, the influences of the waning and waxing moons, even the positions of the stars are all seen as integral to soil health and crop vitality. ” They never went on to explain how the moon and stars affect soil health.
Different Moon Systems
Although many people believe in gardening by moon phases it is not common knowledge that there are actually three different belief systems.
Moon Phases
The more common one is based solely on the phases of the moon. Jackie French explains it well, “Plant growth is supposed to follow the increase or decrease in the Moon’s light. So you plant crops or pick grapes during the waxing (increasing) phase, and harvest crops or cut timber during the waning phase. A refinement says you plant crops like peas whose yield is above ground during the waxing phase, and crops like carrots whose yield is below ground during the waning phase. Note how the refinement contradicts the original view. Other contradictory views exist. Thus one says you should sow seeds just before New Moon so the seeds will germinate and start growing in the waxing phase, while another more widespread view says you should sow seeds just before Full Moon. They can’t both be right.”
Moon Phases and Zodiac Signs
Since the moon passes through the signs of the zodiac it is only natural to conclude that they also affect plants. This belief is more fine tuned and takes both systems into account to decide the right time to plant and harvest.
Sidereal vs Tropical Moon Signs
In this system it is believed that sidereal moon signs are more important than tropical moon signs – whatever they are?
Which System is Right?
In my mind this is one of the big problems with this whole story. When you have three competing beliefs and even the believers can’t agree on which one is true, it really makes you wonder if any of them are valid. If one of these really worked, would someone not be able to show that it worked better than the other two?
Professor Stefan Buczacki, the former chairman of Gardeners’ Question Time on Radio 4 has been quoted as saying “It’s baloney,” he says. “If there was anything seriously in it, why over the centuries has not every gardener or, more importantly, every horticulturalist, followed these maxims? Why is it that people who plant by the moon don’t win all the prizes at the shows, or develop all the new varieties?”
Is Frost More Likely During a Full Moon?
This is a myth I believed for a long time. I discuss it more fully in my book Garden Myths but the bottom line is that there is no correlation between full moons and frost.
Full Moon and Lunacy
But surely it must be true that during a full moon people act more irrational, cause more murders and have more visits to hospital emergency rooms? No, that is not true either.
There is no support to the idea that the phases of the moon affects things like, births, heart attacks, deaths, suicides, violence, psychiatric hospital admissions and epileptic seizures.
Man has come up with many crazy theories about the moon and none are true, not even werewolves.
Rational Thinking About Moon Gardening
Non-believers plant according to calendar dates that reflect the last frost date. In my area the last frost date has always been around May 24. Global warming has thrown that out of whack, but I wanted to see how well the phases of the moon correlated with this date.
I got the date of the full moon that was closest to May 24, for each year between 2000 and 2020. The earliest was May 13 and the latest was June 9. That is a variation of almost 4 weeks.
Even with the current erratic weather the last frost date does not vary that much. Planting by the phases of the moon will surely get warm growing crops killed in some years.
What about other planting zones? Lets assume the phase of the moon is perfect for planting in my garden. Gardeners that are 2 zones warmer or 2 zones cooler will have the full moon on exactly the same day. Is it reasonable to think that the weather and last frost date will be the same in all of these zones?
This is one of these myths that just does not make sense. Why then do so many people believe in planting by the phases of the moon?
I used to believe that frost is more likely on a full moon, but as soon as I saw the data it was clear that my belief was wrong. I no longer believe it. Wouldn’t it be great if the world started believing in facts? Most disagreements and conflicts would end.
With just a cursory glance over the article and comments, I haven’t seen this mentioned yet, but another reason why planting by the phases of the moon isn’t effective is that the phases of the moon (full, waxing/waning, gibbous etc.) is NOT an indication of the distance between the Earth and moon, which is the determining factor for the gravitational forces the moon exerts on Earth’s water.
I couldn’t keep reading after you mistakenly(I hope for your sake!) used “castrated” in place of “castigated” and then went on to claim that the moon causes waves…. tidal bores yes…but ocean waves NO. So much for your “scientific” opinion in lunar gardening!
Wishing you the most interesting of learning experience xo
1) I meant to say “castrated”.
2) According to the National Ocean Service, it is waves, not bores, “The gravitational pull of the sun and moon on the earth also causes waves. These waves are tides or, in other words, tidal waves.”
The link below suggests earth’s molten core has a tidal response to the moon which maintains our magnetic field. This in turn, generates our planet’s electric field which is documented as being useful to plants for bee polination. No signs of the Zodiac just 100 volts per metre and fluid.
https://astronomynow.com/2016/04/01/moon-thought-to-play-major-role-in-maintaining-earths-magnetic-field/
Lots of science here – but no evidence it affects plants.
http://agritrop.cirad.fr/594789/1/s12870-020-2238-4.pdf
Science article, vetted, that confirms moonlight effects plants at a molecular level. “However, in artificial conditions,
our results confirmed that very low luminous intensities
could be perceived by plants and that they had the capacity to modify the transcription of one photoreceptor
and one core clock gene.” Which would relate to waxing and waning and how different plants my respond to either. So, yeah there is scientific evidence and yes it would be related to the phases of the moon because the degree of light potential terrestrial changes with the phases of the moon.
I don’t see anything in this study that shows planting by the moon has any effect on plants.
Scientific Proof of Moon Enhancement
Hello plant people. I love to do my own experiments and I love to raise willow trees. I can’t prove it, but there is something magic about willow trees besides the Salicin in the willow that cures headaches and takes away pain so much faster than Bayer aspirin.
But this is what I can prove…I learned years ago that you can start new willow trees to grow by clipping stems off an existing willow tree, and sticking them in dirt while keeping them soaked in water, until new buds start sprouting all over the place. It takes about 18 days for that to happen.
Now do the same thing under a full moon instead… and viola! It only takes 5 days for the same thing to happen. With the full moon it takes 5 days to get new buds from the willow cuttings verses without the full moon, it takes 18 days to do the same thing.
That is my scientific research experiment regarding the power of the full moon and it’s effects on plant growth. I can’t explain it to you because I don’t know how it works. I just know that it does work and that is all I really need to know. I consider the results of my experiment scientific proof, that a full moon promotes plant growth.
Or more specifically….A full moon dramatically increases plant growth rates in willow trees started from cuttings at the very least..
Go ahead and try it yourself if you are skeptical about what I discovered.
Then you too will know that it is not a myth that the full moon enhances plant growth dramatically.
regards,
Perry Edwards
I’d be happy to ready your write-up of this testing. Important will be the controls you used, and the stats applied to replicates.
That is a nice offer on your part Robert..thank you. I have never attempted a scientific write up of any type so could use the help. As far as controls go… What would you suggest? I just use the same dirt/water/clipping size etc, and basically get the same results of the full moon enhanced clippings starting new buds in 5 days, Without the full moon it takes about 18 days. I have done as many as 200 new starters at one time, but usually do much less than that. They all grow into willow trees if I take care of them and keep them watered. Tell me what you would do so we can get down to business, And thanks again.
-Perry
Start 20 clipping each week – as similar as possible – for a 2 month period. Treat them all the same.
After 7, 14 and 21 days, from the start date of each batch of cuttings, count the number with new buds.
That would give you two moon cycles.
I would expect the number of buds to vary more according to weather and time of year than moon cycle.
Sounds like a plan. I will get the first batch going this weekend. This should be exciting.
Did I ever tell you I was struck by lightning a few years ago when I had a willow stick in my hand? The willow stick took it to ground and I got to see what lightning looks like from the inside out. It is not what you might think.
So get ready for a little Willow Magic Robert. There is much in Mother Nature that is misunderstood.and it will be fun to learn something together.
Dear all, I’ve been “planting by the moon” in some form for bout half a century. More out of habit from working with my grandparents than a belief.
I don’t proclaim that this type of planting has any magical properties but I do find it useful to plan my work; waxing moon for planting, building(positive: productive) and waning moon for weeding, harvesting and slaughter (negative: destructive) work.
But as any gardener/ farmer would tell you, plans are nice and helpful but life happens……:)
Hi, I don’t really believe in planting by the moon, but I found an FA Brown study similar to that you mentioned. “MONTHLY CYCLES IN AN ORGANISM IN CONSTANT CONDITIONS DURING 1956 AND 1957”
I did not grow up with “moon planting”. put seeds in ground. cover. water. wait. most came up. This year I’m going to find out for myself. And yet, so many things come into play as was pointed out. Frost is a factor to consider AS WELL AS the gravitational affect of the moon.
Mostly, I think the affect of the moon’s gravitational pull on the earth is there, just very, very hard to pin down. The light from the moon already came from the sun, so I don’t personally consider that a factor, just makes it easier to see at night sometimes.
I like the example of a magnet and some iron filings. Put the filings under a plate or a piece of paper. Bring the magnet close. It can’t “pick up” the filings because the plate is in the way, but that doesn’t mean the magnetic field doesn’t affect them. The moon’s gravitational field has the same pull on the earth ALL OVER, not just in the oceans. That same gravitational pull can help a plant lift water up its stem. Even though the water would be lifted anyway through transpiration, the pull of the moon’s gravity can make it easier.
Today is a good “above ground crop” planting day. I’m gonna plant some cabbages and pak choi for transplanting. And some direct sown spinach and pak choi under a row cover. Y’all have a good one. =)
There is no evidence the gravity of the moon pulls water up a plant. The internal capillary forces are also at play.
until there is a way to measure the moon’s pull of gravity on the earth, (that’s “measure” not calculate) there won’t be evidence. but when that is there, it “helps”, not causes. When we take “moon” planting too serious that it becomes a religion, its out of place. It IS there and may or may not help. There are the other factors mentioned, covered by the word “weather” too cold too hot too much water, not enough water. Some of which we can control in some amount or other.
Its been a week since I posted. In that time, I have planted (on a good planting day according to the moon) and some seeds didn’t come up. So I replanted and lo and behold, seeds sprouted. My conclusion is if it worked for you, fine. I’m not governing my life around the moon. Or my garden either. There will, however always be a little bit in back of my mind, nagging me. lol Why? because the moon is still there.
lovely when its full, isn’t it ?
What never made sense to me was the idea that at a certain point in time, the moon changes to waxing or waning, and so the advice of moon-phase gardening changes accordingly. However, I live by the ocean, and the tides are the most extreme a few days on either side of the full and new moons. It is never an abrupt change from one day to the next; it is a gradual influence that builds (or decreases) over time. It would seem that if we were to plant according to the greatest (or least) gravitational pull of the moon, we would plan our activities on either side of the moon phases. All the advice in the moon-phase calendars are just a few days off. So, I will stick to planting according to the NOAA forecasts and what has worked in my various microclimates, prune when I can get to it, and harvest when the stuff is ready. Thanks for another great post.
Planting by the moon calendars do recommend plants a day or two before or after the full moon.
I saw that other Facebook post. I was about to come to your defense but that would have meant joining another group and who wants to hang out in places where misinformation is the flavour of the day.
It’s surprising how rigorously people will defend old folk tales and refuse to consider science. I’m sure garden centers love those people if it means more sales.
The light levels given off by the sun and moon are hugely different. For one thing, even though the moon looks bright, it still only reflects between 3 and 12% of the Sun’s light. Therefore if the moonlight had any effect it would be 90% down on what the sun can do.
Also, with alternative theories, why do the effects of these things always have to be thought of as positive. Maybe, the effects of gravity, with full moons etc, have a negative effect on plants. The positive effects are certainly small, or non-existent, but perhaps the real effect, if it exists, is actually negative.
Moonlight has less blue in it’s spectrum, and more red compared to direct sun light . So, even the light is of a different make up.
Plants will have developed to deal with direct sunlight, since it is far more prevalent. Plants in general don’t want green light (or not much) since they reflect it, and the want blue and red light. Upset this balance and you would expect a negative effect.
To detect water level differences in plants and soil due to the moon I would think that you have to control the air pressure and temperature in a very controlled way in order to see the gravitational effect of the moon. I would also think that this would be easy to achieve in a lab – how ever, probably not worth while because outside of the lab you can’t control these two things. Air pressure and temperature have such a huge effect on water any gravitational effect of the moon must be tiny on a tiny body of water.
You can physically see the effects of temperature on water in a kitchen, just pour boiling water in a flask….then watch it shrink as it cools within seconds. You can never see the effect of the moon on a glass of water.
The effects of air pressure on water can be seen in your toilet on a windy day. The air pressure in the drains alters with the wind gusts and you can see the water in the bowl go up and down.
Moon phases can’t have much of an effect, and even if they did, the effect would be happening all the time as the phase changed hour by hour and day by day. No one day would stand out from the day before, or the day after.
Really like the comment of negative effects.
“Also, with alternative theories, why do the effects of these things always have to be thought of as positive. Maybe, the effects of gravity, with full moons etc, have a negative effect on plants. The positive effects are certainly small, or non-existent, but perhaps the real effect, if it exists, is actually negative.” It is positive and negative. Positive for above ground crops is negative for root crops.
the Jury is still out with me. That said, I’m the kind of person who listens but I will find out for myself, not just blindly take someone else’s word for it.