Peasant folklore abounds with strategic advice around gardening or farming with moon phases. Biodynamic gardening pioneered by the legendary mystic / Johan Wolfgang von Goethe scholar Rudolf Steiner had nearly perfected the art of moon phase gardening. Yet in 2026, there remains scant scientific evidence moon phase gardening gives any real advantage.
Even so, many old fashioned gardeners still take the farmers’ almanac approach and plant or transplant at the time of the full moon. With the Summer Solstice approaching and a full moon following shortly after, gardeners have a unique opportunity this year to test these lunar planting theories out. Here we will have both maximum light from the sun and maximum light from the moon.
Many people believe the moon’s effect on tidal water is the same as ground water. The traditional idea is a plant’s roots will chase the ground moisture as the ground water retreats after the full moon, giving the plant a stronger root system. Science says there are too many variables in ground water and aquifer types to have any meaningful impact on the rise and fall of ground water.
But is there any other science available around this phenomenon? Why does planting or transplanting during a full moon seem to always produce results? In 2012 a study recorded in recorded in a book called Enigmi e simboli nelle piante e nei giardini [Mysteries and symbols in plants and gardens], came out of the University of Perugia, Italy. Scientist Isabella Guerrini observed that sap in plants flowed more during the full moon than other times.
Any gardener who neglected a watering can tell you water weight in plants can affect everything from flavor, cell structure, germination, and growth. It seems to be the moisture in plants and the amount of light has more to do with full moon gardening.
Moonlight is 15% the amount of sunlight. It’s also more in the infrared spectrum than uv light. We also know infrared light penetrates the soil further than ultraviolet light because of longer wavelengths.
Those of us who maintain a soft spot for traditional growing methods can now sleep better despite the increased moonlight knowing that their plants outside are maximized for growth success one way or another. With increases in sap flow, changes in moisture above and below ground, infrared light, ultraviolet light, all the other lights we simply can’t rule out the effectiveness of full moon gardening. There’s more than enough science to keep the tradition alive.