The Moon has an effect on the tides. What effects does it have in the garden, how can we use that to our advantage, or is it just a myth?

A Moonlit Garden

I’m not referring to gardening under the moonlight at all. Gardening by the phases of the moon is not anything new or a trend. There is debate from both sides. On one side, it’s folklore and an old wives’ tale. Others like Farmer’s Almanac believe it holds weight. As we all know, the moon affects the tides through gravitational pulls. The moon is the reason our Earth tilts at a 23.5 degree angle and it has a profound effect on things like our seasons and climates. Without the gravitational pull from the moon, there would be havoc on earth. It makes sense that the moon can affect the growth of plants. How does it affect the plants and their surroundings? Does the concept actually work or is it steeped in myth and folklore?

The Concept of Gardening by the Moon

Gardening by the moon or biodynamic gardening is simple concept. Biodynamic gardening relies on the phases of the moon. Like the moon’s effects on the tides, it affects the moisture levels in the soil and plant biology. The timing between the waxing (full moon) and waning (new moon) is important. An example is the full moon and the new moon help with the germination. The soil’s moisture is at its highest levels. The higher moisture levels cause the seeds to swell causing them to germinate. Other concepts in gardening by the moon rely on zodiac signs. There is a lack of evidence for these concepts.

The Founding and Application of Gardening by the Moon

Gardening by the phases of the moon, or biodynamics, is a centuries old concept. It was given its name by Rudolf Steiner who was the founder of the biodynamic approach to agriculture and anthroposophy, a spiritual-scientific approach. In the early 1900s, machinery, synthetically-made fertilizers, and pesticides became common practice. Farmers immediately noticed a deterioration in the soil, animals, and plants. Steiner was sought out to help remedy these degradations. Based on his research, he observed that there was a relationship between the position of the moon in relation to the sun (known as synodic rhythm), planting dates, and crop growth.

Applying Steiner’s Approaches 

There are two individuals who were stands out and proves that biodynamics works.

Dr. Peter Barlow

Dr. Peter Barlow of the University of Bristol in the UK and Maria Thun. Dr Barlow studied a,

”wide range of plant biological topics, e.g. root growth and development, plant cytoskeleton, effects of gravity, plant intelligence, pattern formation, and evolution of eukaryotic cells,” making “numerous contributions to the: elucidation of plant patterns; understanding of root biology; role of the plant cytoskeleton in growth and development; influence of the Moon on terrestrial vegetation; Cell Body concept; and plant neurobiology.”

Citation: Chaffey, Nigel et al. “The botanical multiverse of Peter Barlow.” Communicative & integrative biology vol. 12,1 14-30. 3 Feb. 2019, doi:10.1080/19420889.2019.1575788

One of his most notable pieces of research involved the study of coffee seedlings. His study looked at the co-variation between ultra-weak light emission, the growth of the seedlings, and lunisolar cycles.

Maria Thun

Maria Thun was an influential researcher in gardening who applied Steiner’s anthroposophical philosophy. She wrote several books on the subject, illustrating the optimal days for sowing, pruning, and harvesting. Her books are based on sixty years worth of research. Her work was continued by her son, and now has passed on to her grandchildren. In her findings she noted that the moon influenced all living beings. In the Maria Thun Biodynamic Calendar of 2022, it explains,

“[e]ach constellation is associated with one of the four classical elements of earth, water, air, or fire. And each of these elements affects a different part of a plant: the earth element affects the roots, the water element affects the leaves, the air element affects the flowers, and the fire element affects the fruit and seed. It is easy to understand why: the roots are down in the earth, the leaves are full of water, the flowers’ perfume is carried by the air, and fire (or warmth) is essential for fruit to ripen), (Thun et al., pg. 6)

Thun, Maria, et al. The North American Maria Thun Biodynamic Almanac 2022. Floris Books, 2022.

Using many of Maria Thun’s approaches in a study conducted by Harmut Spiess, “Chronobiological Investigations of Crops Grown under Biodynamic Management. I. Experiments with Seeding Dates to Ascertain the Effects of Lunar Rhythms on the Growth of Winter Rye”, revealed that the greatest effects occurred during the early stages of growth. The phases of the moon helped with germination. Other phases had little to no effect on the plant’s biology.

What are your thoughts on biodynamic principles? Do you think they’d be helpful in your garden?