Planting by the Moon – Science or Myth?

It may seem unscientific to plant by the moon. But there is some logic to the practice. Several years back, I did a test planting with tomatoes, and was impressed enough by the results to swear I’d always pay attention to the moon when gardening. The test plot was small, but the comparative vigor of each set of plants was drastic.

I planted the first set of seeds in sterile, commercial growing medium during the fourth quarter. They took over a week to sprout and some seeds never germinated at all.

About ten days later, during the second quarter, I planted another set of the same seeds in medium from the same bag. The first seedling appeared in three days, and almost every seed had sprouted within five days.

After another three weeks of growth, with both flats of seedlings sharing the same light source, temperatures, and watering care, there was still an obvious difference in vigor. The seedlings planted earlier had weaker stems and smaller leaves than those planted on the later date.

The question was, why?

Not only does the moon add a tiny amount of extra light for plants to grow by when it is full, it also affects gravity here on earth. And gravity affects the flow of water – think of the ebb and flow of the tides. During and just after a full moon, the pull on the earth’s water increases, resulting in the highest tides. According to other research, it also means water in the soil is pulled upward and is more available to germinating seeds. So by planting my tomatoes in the second quarter, just before a full moon, they sprouted just in time to have the best possible access to water in the soil during a critical stage of their growth. Those I planted in the first quarter had just the opposite, with soil moisture at its lowest.

So next time you decide to plant a few seeds, it might just benefit you to look at the night sky. It certainly can’t hurt!

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20 thoughts on “Planting by the Moon – Science or Myth?

  1. Ann Cory

    Awesome post Tam! I’m a big follower of the moon cycles – my body and creativity are often connected to its rhythm, so makes sense to me the moon is connected with nature. Thank you so much for sharing 🙂

    Reply
  2. thebnc

    I’m sending this post to my roommate. She’s the one with the green thumb, I’m the one who plans, and between the two of us, we might get our garden and flower beds looking nice this year!

    Reply
    1. Tam Linsey Post author

      I keep meaning to do more experiments and take better notes and photos, but between writing, family, and garden chores, I never seem to find the time. I’d love to try someday.

      Reply
  3. Pingback: (TBD) Can A Full Moon Affect Behaviour? | David Reneke | Space and Astronomy News

  4. skepteco

    What nonsense! It’s not the moon people, it’s the SUN. Yes, you see the first seeds you planted in your “experiment” were 10 days earlier in the spring when the days were shorter- as every gardener knows, 10 days in the spring can make a big difference! Depending on the weather of course, another very large factor in seed germination -which you make no attempt to control for! A better way to do this kind of trial would be to sow a few seeds every day for a month as was done here: http://undeceivingourselves.org/S-plan.htm What you have done proves absolutely nothing. The brightness of the moon does indeed affect chloroplast activity, but has no effect on when the seeds were planted. Nor does the moon have any effect at all on water in plants or animals- a complete myth (the tides are an effect of the the earth’s rotation combined with the moon’s gravity- which is only discernible on oceans and other very large bodies of water.) Even if there was an effect of the moon on the seeds, it would be impossible to discern against the other obviously much larger factors of the weather and day length, not to mention soil variations from one bed to the next, how deep you sow the seed etc.. All you have done is show your own confirmation bias I’m afraid!

    Reply
    1. Tam Linsey Post author

      Thanks for stopping by, Skeptico. I love a good discussion. The article you referred to is a really good one, but even the testing there is faulty. A true test would need to be performed indoors to eliminate variations in soil temperature, so the only difference was the phase of the moon.

      I should have specified that my seeds were planted indoors, in identical pots and identical soil-less growing medium, with consistent soil and air temperatures. But you are correct that the daylight variation may have effected my results, since I didn’t use artificial lighting directly on the plants. In February, when I planted, that ten day span had a net difference of about an hour of sunlight between the first and second planting.

      So I suppose the question is – are we testing the effect of moonlight on plants, in which case the sun plays a role because we are dealing with natural light sources? Or are we testing a more metaphysical type of “What sun sign is the moon in?” kind of thing. I tend to be more concrete than metaphysical. So your comment has real merit. More sun means better growth.

      I’m always trying to discover an “edge” to gardening, since our season is so short here in Alaska. I appreciate you leaving a comment.

      Reply
  5. Dustin Bajer

    I’ve never tried it but for these reason’s I’m going to guess that if performed multiple times in a well created experiment that there would be no real effect.

    1) Gravity
    From the standpoint of physics, gravity is an absolutely tiny force and is thus only felt when extremely large objects are involved, like the Earth, the Moon, and the worlds oceans. When it comes to soil moisture, however, i’m afraid that gravity would not likely be a contributing factor, as least, not one that would change with the phases of the moon. A much stronger force would be the capillary action between water and your soil.

    2) Moon Phases
    The phase of the moon is determined by where the Moon is relative to the Earth. In essence, the Moon always has a lit side and a dark side. What we see from the Earth depends on where the Earth is relative to the Moon, not because we are somehow closer or further from it.

    One thing in-favour of the theory, though, is the fact that the night’s sky is brighter on a full moon. However, I’m not sure how this extra light would help germinating seed that are planted below the surface of the soil

    Reply
    1. Tam Linsey Post author

      The light is a possible point – I believe at the shallow depth many seeds are planted (lettuce barely wants to be covered) some light may penetrate the soil. Seeds would be far more sensitive to light than we are. I read somewhere that there are weed seeds which can lie dormant for 50 years, buried deep in the soil. The moment they get a brief flash of light, they germinate.

      As far as gravity, plants could be more sensitive to minute forces (like gravity) than we give them credit for. I know you say only large bodies are affected by gravity, but I’m sure glad it holds my feet to the earth 🙂

      With all the feedback I’m getting on this post, I think I may have to do a better, more controlled experiment soon. Or I’d love it if someone has another website or two to point us at where others have experimented using controlled conditions.

      Thanks for the input, Dustin.

      Reply

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