Can the moon affect plants grown indoors? Not moonlight, but it’s influence on water. Harnessing this natural power in the indoor garden environment is possible.

The realization that the moon made water flood and ebb is almost as old as Earth itself. The first written reference to this gravitational influence was made by Pliny the Elder in the 1st century, and farmers throughout history used what is now known as moon phase gardening. Sheer lunacy? Nope. Recent scientific testing over a ten year period at Northwestern University has proven that it isn’t an old myth at all.  There’s a growing number of people who swear by it for more successful growing, and a better harvest. It’s widely used in biodynamic farming and holistic gardening. Since gravity exists indoors, it makes perfect sense that there are benefits to taking advantage of the moon’s influence on your grow room.

Seeds actually absorb more moisture during a full moon. This leads to increased or more rapid germination. Definitely something that any gardener would find useful. Capillary action in the soil works with gravity, and the moon influences soil (and potting media) differently during it’s monthly phases. The plants grown from full moon seeding are also said to exhibit better disease resistance, more robust growth, and give you an earlier, more abundant harvest too. The gravitational affect of the moon also causes heavier or reduced sap in the trunk and stems of plants. Obviously, you would want to do grafting when sap is high for better results.

How does this work?

Planting is best done with plants that bear fruit above ground being planted in the light of the moon, and root vegetables or bulbs being planted in the dark of the moon. Huh? The four quarters of the moon have only 2 steps. Waxing happens while it is approaching, or getting bigger. The waxing moon is also called: new moon, gibbous moon, first quarter moon, and crescent moon. Next comes waning and happens as the moon is receding or shrinking. The waning moon includes the full moon, along with the second quarter moon, disseminating moon, and balsamic moon. Light of the moon seeds are planted by the waxing moon, and dark of the moon seeds are planted by the waning moon.

Water tables rise during the first two quarters of the moon’s monthly phases. Once the moon is full, it starts shrinking, and as it recedes the gravitational pressure lessens and water in the ground recedes with it. The fourth quarter is a time of dormancy, and with the water table and sap at its lowest point makes the perfect time for things like pruning. Why? The wound will bleed far less. For your outdoor garden this is the perfect time for tilling, weeding and other tasks that the moon has no influence over.

That’s the simple explanation.

Moon Phase MonitoringThere is a bit more to the calculations than that. It gets complex and includes the affects of the constellations. This part takes all the mystery out of ancient peoples like the Maya mapping the sky in great detail for guidance on when to plant and when to harvest. They didn’t have irrigation or sprinklers, so working with natural cycles was definitely the way to go. The original modern method that a lot of people now call zodiac gardening was developed by Waldorf educator, Rudolph Steiner who started the biodynamic movement back in 1924. His calculations that are still in use today by serious organic farmers who embrace biodynamic methods, and has nothing to do with astrological signs, and everything to do with astronomical constellations.  The real deal is published every year. The in-depth version by long time biodynamic grower, Maria Thun, The North American Biodynamic Calendar 2014. There is also a simplified version based on Thun’s work available under the title, Stella Natura, which provides guidance for growers in the Northern Hemisphere. For those in the Southern Hemisphere you either have to adjust everything to your time zone, or use the Antipodean Astro Calendar, that is already calculated on Australia time.

Why not use a zodiac gardening calendar? Plants don’t plan their activities by horoscopes. They operate according to natural forces, not plotting their moves using suggestions for their birth sign and rising sign. No two zodiac garden calendars are in agreement, and you would have to know the moment of each seedling’s emergence to fully apply this already dubious method… which translates into faulty theory. If you really want to take advantage of scientific methods proven to harness the natural power of events in the sky over mechanisms of the natural world – you want astronomical calculations – not astrological predictions. The annual calendars linked above are very inexpensive and contain lots of useful knowledge and information.

By the way, there are a few indoor gardeners who have played with moon phase growing and say it does indeed have benefits in the grow room. Working with the moon is free and uses no man-made energy or equipment.



Contributing Writer at Garden Culture Magazine
The garden played a starring role from spring through fall in the house Amber was raised in. She has decades of experience growing plants from seeds and cuttings in the plot and pots.