Biodynamic Digest #2

Originally published 2025-08-03. By Lloyd Nelson, JPI Biodynamics.

Your weekly update on the Biodynamic Astronomical Calendar

Join along as we keep track of celestial opportunities and optimal timing for planting, biodynamic spraying, and more. This week, let’s explore the:

Full Moon and Equisetum

August 9: Full Moon in Capricorn

The focus of this biodynamic digest is identifying the most effective opportunities to apply biodynamic preparations for best results and improving soil health. One of the easiest ways to enhance biodynamic practices is to work with the rhythms and phases of the moon using the biodynamic planting calendar. You don’t need a computer, you don’t need a map. No matter where you are, you have the influence of the moon streaming into your gardens. You can’t patent the effects of the moon, so there’s not a lot of money researching its effects!

With the August 9th full Moon, we biodynamic practitioners have a fantastic opportunity to boost soil and plant health.

Water is Life

“Water, in effect, is eminently suited to prepare the ways within the earthly domain for those forces which come, for instance, from the Moon. Water brings about the distribution of the lunar forces in the earthly realm. There is a definite connection between the Moon and the water in the Earth.”1

In biodynamics, we use water to concentrate and then carry the biology and energetic forces contained in biodynamic preparations as we distribute them over the land we tend.

To increase soil health, we can use Biodynamic preparations at the optimal time for best results. One of the simplest and easiest to make and use Biodynamic preparations is the common horsetail herb, Equisetum arvense.

“Equisetum is a wild plant and a primordial plant, ancient beyond reckoning. In its former glory, great prehistoric equisetum plants grew to 100 feet tall, towering over a landscape that was so humid you could only see shadowy shapes in the fog like some primeval old moonlit Pangaean everglades. But the distant past is never far away – albeit in humbler forms, a memory of the past always persists in the present.”2

Equisetum

My first meeting with the great biodynamic teacher Hugh Courtney was in the autumn of 1996, at the Josephine Porter Institute for Applied Biodynamics in Virginia. Here, Hugh introduced me to the making and use of the nine Biodynamic preparations at one of the famous JPI Fall Biodynamic Practicums. Hugh was a very stoic and mission-driven individual. Hugh instilled in us the urgency to make and use Biodynamic preparations “so the Earth may be healed.” Much of biodynamic knowledge is not written down, but is a living oral tradition from practitioner to practitioner. Hugh often shared with us unwritten keys for improving biodynamic practices.

One of Hugh’s favorite biodynamic preparations was BD 508, equisetum arvense, the common horsetail herb. Though this herb is not always counted among the preparations in Europe (where counting often stops at 507), Dr. Ehrenfried Pfeiffer numbered equisetum as 508 among the nine preparations. Hugh taught that there are nine biodynamic preparations, and we should use all of them for optimal results.

Hugh Courtney had an underground root cellar for storing biodynamic preparations. Descending the steps and entering the cool, dark, and damp space, you could always find a large earthenware crock full of fermenting equisetum tea in the corner just inside the underground entrance. Hugh would quite proudly show off his batch of fermented equisetum tea to his visitors on one of his famous root cellar tours. He would talk about the importance of fermentation and the necessity of using horsetail tea to enhance the effectiveness of biodynamics on the farm. Hugh would wait til everyone had gathered around the crock filled with fermented tea, and then with a sly smile, he would lift the lid to show what was happening. First, you would be greeted by the “characteristic smell” of well-fermented Equisetum tea, and this is unforgettable. Then you would observe a rich, olive-green tea gently bubbling in the crock.

Periodically, Hugh would add freshly made horsetail tea to the fermenting batch to replenish what he had used and to keep the fermentation going continuously. Most importantly, he wanted to show us how simple and easy it is to make and use the Biodynamic horsetail herb.

Hugh taught us that BD 508 equisetum herb and BD 501 Biodynamic Horn Silica were the two most underutilized biodynamic preparations, and he encouraged biodynamic practitioners to use them more often. If you are unable to locate and harvest the equisetum herb growing in its natural habitat, you can purchase it from one of the several distributors of Biodynamic preparation.

A farm in Virginia might be situated above the Chesapeake Bay Reservoir, which is constantly refilled from the water in the bay. By contrast, Australia has greatly restricted ground water resources – the driest continent on earth. It isn’t just that plants grow differently with water below them – entire ecosystems express themselves radically differently where there is not plentiful water below plants. In North America, we often face the problem of excessive water.

A misconception had developed around the light being “brighter” in North America, which is patently not true. Somewhere like Australia, perhaps one could better argue that the drying silica light effect might not be as urgently needed, but North America is a continent full of water reservoirs beneath it. You could almost say that in much of the eastern United States, you have an example of the waters below meeting the waters above, while in arid regions, you are essentially missing the waters below and depend much more on the mercy of rain from above.

Even what is necessary for life, in excess, becomes a poison. When we have “a wet winter followed by a wet spring” (as Steiner suggests), we may have conditions of excessive wateriness that must be overcome. To do so, we reach for the humble plant, Equisetum arvense.

Before moving to Colorado a dozen years ago, I was managing a farm in Hawaii. Not finding any Equisetum arvense growing anywhere on the islands, I was able to locate a suitable substitute replacement plant: Casuarina equisetifolia—the common ironwood tree. In tropical areas and in the southern hemisphere where Equisetum may be hard to impossible to find growing, the best substitute for equisetum is the ironwood tree. Commonly known as the she-oak, ironwood, or horsetail casuarina, this tree is native to Australia and Southeast Asia. The structure of ironwood leaves is quite similar in appearance to the equisetum plant and is commonly used as a suitable substitute for this particular biodynamic preparation. On a recent trip to make biodynamic preparations in central California, I observed a grove of healthy, well-established Ironwood trees growing on the edge of a large paved parking lot next to a convenience store. You never know where you may find things happening in Nature, so always, always in Biodynamics, we want to use our powers of observation.

Equisetum is one of the easiest of the biodynamic preps to make and use. You just have to look at it: it is all stem and it never suffers from mildew even when growing in waterlogged conditions. Whether you think of it as spiritual “forces” or phytonutrients, equisetum in the form of a tea can give plants exactly what they need to be resilient against excessively watery conditions.

Equisetum is as close as you can get to a photosynthesizing crystal. It has no true fruits, no true flowers, no true seeds – not even fully developed roots. Equisetum is the only known plant for which silicon is not just beneficial but necessary for it to live. It cannot live without silicon. “Silicon is used in large amounts to play important roles in most plants, but has proved essential only for diatoms and plants in the Equisetaceae family.” (Brady and Weil, The Nature and Properties of Soils, 14th edition, pg. 7) As the only known plant to require silicon assimilation as a necessary part of its existence, we can use it to transfer this power to absorb silicon to our other plants.

In biodynamics, we simply make a strong tea with equisetum, dilute the concentrate in water, stir, and then spray it onto plants.

The dried horsetail (you can use fresh this time of year if you can find it growing) is made into a tea or an infusion, diluted, and then sprayed on soil and plants. If the tea ferments and ripens after a few days, it is generally best to use it as a soil spray. You can tell when the equisetum tea has fermented by its characteristic sulfury odor.

In our decade-long scientific soil health research trials in Colorado, we have used equisetum tea as a foundation in our health, vitality, and fertility program. We use equisetum tea as a fertilizer and as a beneficial fungal booster. Using equisetum tea strengthens the plants and helps make them insect and disease-resistant.

Biodynamics’ emphasis on observation and the living farm organism’s whole-scale approach asks us to look far and wide for opportunities to improve our soil health practices.

In our prolonged research project, we continue to study the science to help us interpret and further develop biodynamic best practices. We are interested in the best timing to trigger positive reactions in plants and soil through the use of biodynamic preparations.

Rick Haney, creator of the Haney Soil Health Test, has this to say about our biodynamic work:

“Here’s my take on it. The soil is telling us, trying to communicate with us, what is going on. There are triggers in the soil. I am convinced there are certain chemical triggers in the soil that connect plants and microbes, that they communicate and that things can happen quickly when the right things come together. And what Sustainable Settings has accomplished in the last decade with their combined regenerative and Biodynamic land management, that is demonstrated in their seven years of soil data, is proof of it.”3

Harnessing Lunar Energies

“[T]he Moon reflects everything that comes towards it.. the whole starry heavens are reflected by the moon and stream towards Earth.”4

The power to restrict Moon forces goes hand in hand with knowing how to enhance them as well. The few days around the full Moon are one of the easiest times to “trigger” positive results in building soil health. Timing is everything in biodynamics, so it's best to make the most out of it! If you are seeking to enhance the lunar-earthly side of things, say, in a drought, you will want to draw on preparations like BD 500, BC, or the Buffalo Soil Activator in the 48 hours before a full Moon. By contrast, if you wish to mute the effect of too much water, you may want to consider using equisetum instead during the 48 hours before the full Moon. Similarly, Equisetum tea can be used during a LEAF/Water time on the biodynamic calendar to increase moisture, or during a FRUIT/warmth time to decrease moisture. Equisetum is a plant that helps establish proper balance in the soil.

Equisetum tea sprayed at or near the full Moon helps strengthen plants tremendously, giving superior resistance to detrimental fungi, insects, and diseases. Equisetum is rich in plant-available silicon (Si), which is the single agricultural element that helps make plants resilient against biotic (pests, diseases, fungi, etc.) and abiotic (droughts, floods, heat, cold, etc.) stress. Most of the silicon in the Earth is locked up in the form of sand or clay, but in equisetum, it is in a living form. Equisetum is known as a biosilicifier, and the form of silica it accumulates is amorphous hydrated silica, which does not have a hexagonal form, in contrast to BD 501 quartz silica, which keeps its hexagonal form. In the mineral realm, amorphous silica is seen in opals. So the kind of silica being communicated to plants by BD 508 is quite distinct from what is imparted by BD 501.

By using equisetum tea in your garden, you will have more vigorous plants, increased resistance to insects and diseases, and improved soil health. The power to direct what descends from the cosmos with our own two hands is one of the most remarkable gifts in nature.