Biodynamic Agriculture

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What Biodynamic Agriculture Is

Biodynamic agriculture is the first organized organic-farming movement, originating in Rudolf Steiner's 1924 Agriculture Course at Koberwitz, near Breslau. It treats each farm as a single self-sustaining living organism and times sowing, cultivation, and the use of nine herbal and mineral preparations to cosmic and seasonal rhythms.

The method predates the word "organic" by roughly two decades. When Steiner delivered his eight lectures from June 7 to 16, 1924, in the home of Count and Countess Keyserlingk, chemical agriculture built on Justus von Liebig's nitrogen-phosphate-potassium model was already the orthodoxy across Europe. Steiner's course set out a deliberate counter-position. As the chemist Ehrenfried Pfeiffer, one of his closest agricultural collaborators, recorded the event, "In the Agricultural Course, which was attended by some sixty persons, Rudolf Steiner set forth the basic new way of thinking about the relationship of earth and soil to the formative forces of the etheric, astral and ego activity of nature." Pfeiffer, who developed the sensitive-crystallization method used to test biodynamic preparations, noted that the lectures grew out of farmers' alarm at a concrete, measurable decline: seed-strains degenerating within a few generations, lucerne crops that once held a field for thirty years failing after four or five, and rising sterility and foot-and-mouth disease in livestock.

The farm as a single organism

The central idea of biodynamics is that a farm is not a collection of separate enterprises but one integrated being. Soil, compost, pasture, crops, livestock, wildlife, and the people who work the land are understood as organs of a larger whole, each contributing to and drawing from the others. In the language the movement adopted from Steiner, the goal is a self-contained agricultural individuality: a farm that produces its own fertility from within rather than importing it. According to the Biodynamic Association (biodynamics.com), the founding professional body for the method in North America, this means a farm should ideally generate its own manure, feed, and seed, keeping nutrients cycling on the land instead of buying in fertility and exporting depletion.

That principle has direct, practical consequences. Livestock are kept in proportion to the acreage that can feed them and absorb their manure, so the herd size is set by the land rather than by market demand alone. Crop rotations are designed to build humus rather than mine it. Compost made on the farm, treated with the biodynamic preparations, becomes the engine of soil fertility. The aim is closure of the loop: the fewer inputs crossing the farm boundary, the healthier and more genuinely self-sustaining the organism is judged to be. This holistic, whole-system framing is what most clearly distinguishes biodynamics from a simple checklist of permitted and prohibited substances. It is also where the method touches the wider Steiner worldview, the relationship between the plant and the cosmos that runs through all of his nature teaching.

This emphasis on self-containment was present from the start. Steiner's collaborators recorded that he urged farmers to make their enterprises as independent of bought-in materials as possible, and to treat the work as a long-term experiment in practice rather than as a fixed recipe. Pfeiffer recalled that translating the basic ideas "into actual practice" took years of trial: working out which crop rotations "build up rather than deplete humus," how to handle manure and compost, and how to integrate the breeding and care of cattle into the rhythm of the whole farm. The farm-organism is therefore less a static blueprint than a management ideal that each piece of land approaches in its own way, according to its soil, climate, and the judgment of the people working it.

Beyond chemical agriculture

Biodynamics was conceived as an alternative to the mineral-fertilizer paradigm, not merely a softening of it. Pfeiffer described the two outlooks as confronting "one another from opposite points of the compass." Liebig's followers, he wrote, reduced plant nutrition to a "nutrient-need" satisfied by nitrogen, phosphates, potassium, and calcium, while the biodynamic school insisted that soil itself is alive and that plant health depends on more than soluble salts. Steiner's collaborators recognized in the 1920s and early 1930s what Pfeiffer called "the earth as a living organism," along with the central importance of humus and soil life, decades before such ideas entered mainstream agronomy. Much of that biological insight has since become uncontroversial. The "dynamic" half of the method, the claim that cosmic and formative forces shape growth, remains outside what conventional science accepts.

The evidence picture is genuinely mixed, and it is worth stating plainly. The strongest support for biodynamics comes from soil and biodiversity research rather than from any validation of cosmic rhythms. The DOK trial run by the Research Institute of Organic Agriculture (FiBL) in Switzerland, a side-by-side comparison of bioDynamic, bioOrganic, and Konventionell systems running since 1978, found that the biodynamic plots had higher soil microbial biomass and activity, better aggregate stability, and greater earthworm and beneficial-insect populations than the conventional plots. What the trial did not isolate was any effect attributable specifically to the preparations or to celestial timing as opposed to the underlying organic management of compost and rotation. Controlled tests of the planting calendar, including Maria Thun's lunar-rhythm claims, have generally failed to reproduce the predicted yield differences under blind conditions, and the homeopathic dilutions of the preparations have no accepted mechanism in plant physiology. Honest accounts of the method therefore separate two things: a whole-farm organic practice with measurable benefits for soil life, and a set of cosmological claims that lack peer-reviewed support.

Two features set biodynamics apart from all later forms of organic farming. The first is the set of nine preparations, numbered 500 through 508 by the Biodynamic Association: field sprays made from cow manure (500) and ground quartz (501) fermented in cow horns buried over winter, and six compost preparations made from yarrow, chamomile, stinging nettle, oak bark, dandelion, and valerian, applied in homeopathically small quantities. The first batch of preparation 500 was buried at the Sonnenhof in Arlesheim, Switzerland, and dug up in Steiner's presence in the early summer of 1924, an event Pfeiffer witnessed and recorded in detail. The second distinguishing feature is timing: many practitioners follow a planting calendar keyed to lunar and zodiacal cycles, an approach later codified by Maria Thun, whose annual sowing calendar has guided biodynamic growers since 1963.

Relationship to and precedence over organic farming

Biodynamics holds a specific place in agricultural history: it is the seedbed from which the wider organic movement grew. The 1924 course and the network of farmers and scientists that formed around the Natural Science Section of the Goetheanum predate Sir Albert Howard's An Agricultural Testament (1940), Lord Northbourne's coining of the term "organic farming" (1940), and J. I. Rodale's American organic publishing of the 1940s. Several historians of the movement, including Philip Conford in The Origins of the Organic Movement (2001), trace direct lines of influence from biodynamic practitioners, Pfeiffer chief among them, into early British and American organic circles.

Today biodynamics functions as a distinct standard that sits alongside, and in most respects above, conventional organic certification. Farms are certified through Demeter International, founded in 1928 and now operating in more than fifty countries, with Demeter USA administering the standard in the United States. Demeter certification requires everything organic certification does, then adds the whole-farm-organism requirement, mandatory use of the preparations, and limits on imported fertility. In practice this makes biodynamics both the oldest branch of organic agriculture and one of its most demanding: an organic farm need not be biodynamic, but a Demeter-certified farm must satisfy organic criteria and then go considerably further.

The Farm as a Living Organism

The principle that organizes every other practice in biodynamic agriculture is the idea that a farm should be treated not as a production site but as a single living being. In the lectures Steiner gave at Koberwitz in June 1924, later published as the Agriculture Course (GA 327), he framed soil, plants, animals, manure, and the surrounding terrain as organs of one body whose health depends on their working together. Ehrenfried Pfeiffer, the chemist who worked closest to Steiner on the practical side of the movement, recorded that what bio-dynamic circles grasped as early as 1924 was "the significance of soil-life, the earth as a living organism, the role played by humus, the necessity of maintaining humus under all circumstances, and of building it up where it is lacking." That phrase, the living organism, is the seed of the whole approach.

The Biodynamic Association (biodynamics.com) gives this idea its working name: the farm individuality, or the farm organism. Each farm, in this view, has its own character set by climate, soil, water, the species that thrive there, and the people who tend it, and the farmer's task is to develop that individuality rather than override it with standardized inputs. Demeter International, which certifies biodynamic farms worldwide, builds the concept directly into its standard: a Demeter farm is required to function as a self-contained, closed system to the greatest degree practicable, generating its own fertility and feed from within its own boundaries rather than importing them. Steiner did not use the English words "self-contained individuality," and that exact phrasing should be credited to the later movement, but the orientation toward self-sufficiency is consistent with the course he gave.

Steiner stated the farm-individuality ideal directly in the second Koberwitz lecture, framing self-sufficiency not as a rule but as the natural and healthy condition of a farm:

Whatever you need for agricultural production, you should try to posses it within the farm itself (including in the “farm,” needless to say, the due amount of cattle). Properly speaking, any manures or the like which you bring into the farm from outside should be regarded rather as a remedy for a sick farm. That is the ideal. A thoroughly healthy farm should be able to produce within itself all that it needs.

Rudolf Steiner, Agriculture Course (GA 327), Lecture 2, Koberwitz, June 1924

The closed nutrient cycle

The practical expression of the farm-organism idea is a closed, or nearly closed, nutrient cycle. In an industrial model, fertility is something a farm buys: nitrogen fixed from the air by the energy-intensive Haber-Bosch process, phosphate and potash mined and shipped in, feed trucked from distant grain belts. In the biodynamic model, fertility is something a farm circulates. Crops feed people and animals; animals return manure; manure, composted on the farm and treated with the biodynamic preparations, rebuilds the humus that grows the next crop. Pfeiffer noted that the priorities to be worked out in practice were exactly these recycling problems: "what crop rotations build up rather than deplete humus" and the handling of "soil treatment, crop rotation, manure and compost." Nothing essential is meant to leave the cycle except the food sold off the farm, and even that loss is to be minimized and, where possible, balanced by composting what can be returned.

This is the sharpest contrast with the system that Steiner and Pfeiffer were reacting against. The chemically minded agriculture of their day rested on the work of Justus von Liebig and his followers, who, in Pfeiffer's account, reduced plant growth to a "nutrient-need" satisfied by "nitrogen-phosphates-potassium-calcium." A farm run on that logic does not need to be a whole organism, because any deficiency can in principle be bought and poured on. The biodynamic objection is not that nutrients are unreal but that a farm dependent on continuous external inputs has no inner life of its own and slowly loses the soil biology that makes it self-sustaining. Notably, Pfeiffer observed that Liebig himself "expressed doubt as to whether the N-P-K theory should be applied to all soils," having seen that deficiency symptoms were "more apparent in soils poor in humus than in those amply supplied with it."

The essential role of animals

No animal, no organism: integrated livestock are not optional in the biodynamic conception but the engine of its fertility. Cattle hold a special place. Steiner devoted sustained attention in the course to the cow, its digestion, and its manure, and Pfeiffer lists among the matters that had to be settled in practice "manure and compost handling, time-considerations in the proper care and breeding of cattle." Manure is the medium through which the farm metabolizes its own residues back into fertility, and it is also the raw material for several of the field and compost preparations. The Biodynamic Association recommends roughly one livestock unit per hectare or so as a rule of thumb for keeping a farm's nutrient budget in balance, and Demeter standards require certified farms to keep ruminants, treating an animal-free farm as an incomplete organism that must lean on imported fertility.

The contrast with confined industrial animal production is deliberate. In the industrial system, animals are concentrated in feedlots distant from the land that grows their feed, so manure becomes a waste-disposal liability at one end of the supply chain while the cropping ground at the other end depends on synthetic nitrogen. The biodynamic farm closes that loop on a single piece of ground: the same animals that eat the farm's forage fertilize the farm's fields.

For Steiner the value of that manure was not only chemical. In the third lecture he described nitrogen, which the dung carries back into the soil, as the mediator that binds life to spirit:

Nitrogen is for ever dragging the living to the spiritual principle. Therefore, in man, nitrogen is so essential to the life of the soul. For the soul itself is the mediator between the Spirit and the mere principle of life. Truly, this nitrogen is a most wonderful thing. If we could trace its paths in the human organism, we should perceive in it once more a complete human being.

Rudolf Steiner, Agriculture Course (GA 327), Lecture 3, Koberwitz, June 1924

Biodiversity, hedgerows, and habitat

Because the organism is meant to be whole, biodynamic management treats the uncultivated parts of a farm as working organs rather than wasted ground. Hedgerows, woodlots, ponds, wetlands, and field margins provide habitat for pollinators, birds, and predatory insects that keep pest populations in check, and Demeter International requires that a set proportion of a certified farm, commonly cited as around ten percent, be set aside for biodiversity. This habitat thinking has a root in the course itself. In one of the passages Pfeiffer quotes, Steiner described using a small piece of wild ground as a pest-control organ: "where there is even a small mushroom-infested meadow near a farm, the fungi, owing to their kinship with the bacteria and other parasites, keep them away from the farm. It is often possible, by infesting meadows in this way, to keep off all sorts of pests." Whether or not the mechanism is as Steiner described, the instinct to manage the whole farm, cultivated and wild together, as one functioning system is characteristic.

Here the evidence record is mixed in a way worth stating plainly. The claims specific to biodynamics, that the preparations and cosmic rhythms add something beyond good organic husbandry, lack solid peer-reviewed support, and controlled trials such as the long-running DOK trial in Switzerland have struggled to separate biodynamic effects from those of the organic management they share. But the organism-level practices, diverse rotations, integrated livestock, on-farm composting, and conserved habitat, rest on firmer ground: agronomic and ecological research consistently links such practices to higher soil organic matter, greater microbial activity, and richer on-farm biodiversity. The farm-as-organism principle, in other words, is the part of Steiner's vision that maps most readily onto mainstream agroecology, even where its mystical framing does not. Readers who want the philosophical background to that framing will find it in our companion entries on the spirits of plant growth and on the wider system of biodynamic thought.

The Biodynamic Preparations

At the heart of biodynamic practice sit nine numbered substances that distinguish the method from all other forms of organic farming. Rudolf Steiner first described how to make them in 1923, a year before he gave the eight lectures of the Agricultural Course at Koberwitz in June 1924. According to Ehrenfried Pfeiffer, the chemist who became the method's chief early practitioner, Steiner gave the recipes flatly, "simply giving the recipe without any sort of explanation, just 'do this and then that.'" The preparations were assigned the catalogue numbers 500 through 508 by the early experimental circle, and those numbers remain in use by the Biodynamic Association and Demeter International today. They fall into three groups: two field sprays (500 and 501), six compost preparations (502 through 507), and a ninth substance, horsetail (508), used as a plant tea against fungal disease.

Steiner framed the preparations as ways of drawing what he called cosmic or formative forces into the soil and plant. Pfeiffer records his insistence that "the benefits of the bio-dynamic compost preparations should be made available as quickly as possible to the largest possible areas of the entire earth, for the earth's healing." The quantities involved are extremely small. The preparations are not fertilizers in the conventional sense, a fact that drew open ridicule in the years 1924 to 1930, when, as Pfeiffer recalled, the biodynamic preparations were dismissed "because plants cannot possibly be influenced by high dilutions." That objection has never been fully answered by peer-reviewed science, a point examined later in this pillar.

The two field sprays: horn manure (500) and horn silica (501)

Preparation 500, horn manure, is the signature biodynamic substance. The Biodynamic Association and Josephine Porter Institute describe its making as follows: cow manure is packed into a cow's horn, which is then buried in fertile soil over the winter months, roughly from the autumn equinox to the spring equinox. Over winter the manure transforms into a dark, sweet-smelling, humus-like material. A small amount, on the order of a single horn's contents (about 60 to 100 grams) per acre, is stirred into roughly 30 to 40 litres of warm water for a full hour and sprayed onto the soil in large droplets, typically in the late afternoon. Its stated purpose, per the Biodynamic Association, is to stimulate root growth, soil microbial life, and humus formation.

Steiner gave his own account of why the horn is used in the fourth lecture, presenting preparation 500 as a way of holding the forces of the living cow inside the buried horn over winter:

You see, by burying the horn with its filling of manure, we preserve in the horn the forces it was accustomed to exert within the cow itself, namely the property of raying back whatever is life-giving and astral. Through the fact that it is outwardly surrounded by the earth, all the radiations that tend to etherealise and astralise are poured into the inner hollow of the horn. And the manure inside the horn is inwardly quickened with these forces, which thus gather up and attract from the surrounding earth all that is ethereal and life-giving.

Rudolf Steiner, Agriculture Course (GA 327), Lecture 4, Koberwitz, June 1924

The corpus preserves a vivid first-hand account of how the stirring and spraying were first taught. Pfeiffer describes the moment the first batch of 500, buried at the Sonnenhof garden in Arlesheim, Switzerland, was dug up in the presence of Steiner in the early summer of 1924:

Dr. Steiner turned back, called for a pail of water, and proceeded to show us how to apportion the horn's contents to the water, and the correct way of stirring it. As the author's walking-stick was the only stirring implement at hand, it was pressed into service. Rudolf Steiner was particularly concerned with demonstrating the energetic stirring, the forming of a funnel or crater, and the rapid changing of direction to make a whirlpool.

Ehrenfried Pfeiffer, introduction to Steiner's Agriculture Course (GA 327)

That account names the two features biodynamic growers still treat as essential: stirring vigorously enough to draw down a central vortex, then reversing direction to throw the water into chaos before a new vortex forms. The Biodynamic Association calls this alternating motion "dynamizing," and holds that the rhythmic creation and collapse of the vortex is what activates the preparation. Pfeiffer adds that Steiner then gave "brief directions" on spraying and "indicated with a motion of his hand over the garden how large an area the available spray would cover." Practitioners regard this demonstration as the working birth of the field-spray practice, even though the detailed stirring protocol was elaborated by the experimental circle in the years that followed rather than fixed in the lectures themselves.

Preparation 501, horn silica, is the counterpart spray. The Josephine Porter Institute and Demeter USA describe grinding quartz (silica) crystal to a fine flour, mixing it to a paste, and packing it into a cow's horn that is buried through the summer rather than the winter. The resulting powder is used in tiny amounts, often a gram or less per acre, stirred for an hour and sprayed as a fine mist onto the growing crop, usually early on a sunny morning. Where 500 is said to work downward into the soil and root, 501 is said to work upward and with light, and biodynamic growers apply it to support photosynthesis, the upright growth of the plant, and the flavour, aroma, and keeping quality of the harvest. The two sprays are thus treated as a polar pair, one earthly and lunar, the other cosmic and solar.

The six compost preparations (502 to 507)

The remaining preparations are inserted in minute quantities into compost heaps, manure, or liquid manures rather than sprayed on fields. Each is made from a specific medicinal plant, and in most cases the plant material is sheathed in an animal organ and buried or hung through a season before use. According to the Biodynamic Association and Demeter, a complete set is added to a single compost pile in small doses, the idea being that they regulate and direct the decomposition process and help the finished compost carry balanced forces into the soil. The six, by number, herb, and stated function, are:

• 502, Yarrow (Achillea millefolium). Yarrow flowers are packed into a stag's bladder, hung in the sun over summer, then buried over winter. The Biodynamic Association associates it with sulphur and potassium processes and with the plant's capacity to "make the best of even the most diluted substances."
• 503, Chamomile (Matricaria chamomilla). Chamomile flowers are stuffed into cow intestines, formed into a sausage, and buried over winter. It is connected with calcium and the stabilising of nitrogen, said to keep the compost's nitrogen from being lost and to enliven the soil.
• 504, Stinging nettle (Urtica dioica). Whole flowering nettle plants are buried directly in the ground, surrounded by peat, for a full year. Demeter describes it as a "sensitizer" that brings reason and balance to the soil, aiding the proper interplay of iron and nitrogen and improving the chlorophyll and humus content.
• 505, Oak bark (Quercus robur). Ground oak bark is placed inside the skull of a domestic animal and buried over winter in a wet, marshy spot or where water flows. Rich in calcium, it is used by practitioners to counter plant diseases and what biodynamics describes as rampant, unhealthy growth.
• 506, Dandelion (Taraxacum officinale). Dandelion flowers are sewn into the mesentery (the membrane around a cow's intestines) and buried over winter. Linked to silica and potassium, it is said to help the plant draw what it needs from the wider environment and to make the soil "sensitive" to the influences around it.
• 507, Valerian (Valeriana officinalis). Unlike the others, valerian is used as a liquid: the juice is pressed from the flowers, diluted, stirred, and sprayed over the finished compost pile. The Biodynamic Association connects it with phosphorus and says it forms a protective warmth-skin around the heap and stimulates the other preparations within it.

Pfeiffer and later biodynamic writers stress that the organ sheaths are not arbitrary. In Steiner's reasoning, organs such as the bladder, intestine, mesentery, and skull continue to mediate the specific life processes they served in the living animal, concentrating the herb's action. No peer-reviewed evidence supports that mechanism, and it remains the most contested element of the practice. Some controlled studies, including the long-running DOK trial in Switzerland begun in 1978, have reported greater microbial activity and soil organic matter under biodynamic management, though researchers have generally been unable to isolate any effect of the preparations themselves from the effects of composting and organic management.

The ninth preparation: horsetail (508)

Preparation 508 stands apart from both the sprays and the compost set. It is made from common horsetail (Equisetum arvense), a plant unusually high in silica. The Biodynamic Association and Josephine Porter Institute describe simmering the dried herb in water to make a tea, sometimes fermented, which is then diluted and sprayed onto soil and foliage. Its purpose is not to feed the plant but to suppress fungal disease and damp, watery, mildew-prone conditions, drawing on the same silica-and-light polarity that 501 represents. Unlike 500 through 507, it is applied as needed in response to disease pressure rather than on a fixed seasonal schedule, which makes it the preparation closest in function to a conventional plant treatment.

Taken together, the nine preparations form a closed system that biodynamic certification bodies treat as non-negotiable. To carry the Demeter mark, the international biodynamic certification standard administered by Demeter International, a farm must make or obtain and apply the full set. They are the practical core of what Steiner set in motion at Koberwitz, and the clearest line separating biodynamics from organic farming as it is otherwise understood. The reasoning behind them, that specific living processes can be concentrated and redirected, belongs to the same Goethean and anthroposophical stream that produced Steiner's account of plant metamorphosis and his wider Goethean science.

Cosmic Rhythms and the Planting Calendar

What separates biodynamics most sharply from ordinary organic farming is its claim that plant growth answers not only to soil and weather but to the movements of the moon, the planets, and the stars. Rudolf Steiner laid the groundwork for this idea at the 1924 Koberwitz course, where he framed agriculture as a meeting of earthly substance and what he called cosmic forces. Ehrenfried Pfeiffer, the chemist who became Steiner's closest agricultural collaborator, recorded that the course "set forth the basic new way of thinking about the relationship of earth and soil to the formative forces of the etheric, astral and ego activity of nature," and that "the health of soil, plants and animals depends upon bringing nature into connection again with the cosmic creative, shaping forces." For Steiner and his followers, a seed is not merely a parcel of genes and stored starch but a node where these forces enter the living world. The practical question that follows is one of timing: if cosmic influences shape growth, then the moment of sowing, cultivating, and harvesting should matter.

The formative forces concept

Underlying the whole system is the notion of formative or etheric forces, a vocabulary Steiner drew from his anthroposophy rather than from chemistry or physics. In the biodynamic picture, two streams act on a plant. Earthly or terrestrial forces, working through water and mineral substance, build up root and stem from below. Cosmic forces, carried chiefly by light and warmth, stream in from the periphery and govern flowering, fragrance, ripening, and seed. Pfeiffer's account quotes the Soviet agronomist W. R. Williams to make the contrast vivid: "The cosmic factors, light and heat, act directly on the plant, whereas the terrestrial factors act only through an intermediary (substance)." Steiner went further than any agronomist of his day in insisting these cosmic factors carry not just energy but form-giving, shaping qualities, and that different constellations stamp different "signatures" on the plants growing beneath them. Pfeiffer connected this to an older European tradition, the late-medieval "doctrine of signatures" running back through Albertus Magnus to Theophrastus, in which "relationships exist between certain cosmic constellations and the various plant species. These constellations are creative moments under whose influence species became differentiated and the various plant forms came into being."

Steiner set out this polarity in his own words in the opening lecture, describing how the silica nature opens the plant to the distant planets while the lime nature carries the reproductive forces of the nearer ones:

The silicious nature opens the plant-being to the wide spaces of the Universe and awakens the senses of the plant-being in such a way as to receive from all quarters of the Universe the forces which are moulded by these distant planets. Whenever this occurs, Mars, Jupiter and Saturn are playing their part. From the sphere of the Moon, Venus and Mercury, on the other hand, is received all that which makes the plant capable of reproduction.

Rudolf Steiner, Agriculture Course (GA 327), Lecture 1, Koberwitz, June 1924

Steiner also pointed to daily rhythms of light. Pfeiffer reports that the Goetheanum researcher Joachim Schultz set out to test "Dr. Steiner's important indication that light activity acts with growth-stimulating effect in the morning and late afternoon hours, while at noon and midnight its influence is growth-inhibiting." It is worth being precise about what the historical course material does and does not contain. Steiner sketched a worldview of cosmic forces and gave a few specific timing indications, but he did not publish the detailed sowing calendar that practitioners now use. That structure was built decades later by others working in his tradition. The deeper metaphysics of these etheric forces, and how Steiner distinguished them from ordinary physical energy, is set out in our entry on the plant and the cosmos.

Maria Thun and the sowing calendar

The biodynamic planting calendar in its familiar form is the work of Maria Thun (1922 to 2012), a German farmer and researcher who began systematic field trials in 1952 and published her first annual Aussaattage (Sowing Days) calendar in 1962. Thun grew radishes and other crops sown at different points in the moon's monthly passage through the zodiac and recorded differences in yield and form. From these trials she developed the calendar's central scheme, which sorts each day into one of four types keyed to the four classical elements and the four parts of the plant.

• Root days fall when the moon stands before an earth constellation (Taurus, Virgo, Capricorn) and are held to favor root crops such as carrots, beets, and potatoes.
• Leaf days fall before a water constellation (Cancer, Scorpio, Pisces) and are recommended for leafy crops such as lettuce, cabbage, and spinach.
• Flower days fall before an air constellation (Gemini, Libra, Aquarius) and are linked to flowering plants and to crops grown for their blooms.
• Fruit days fall before a fire constellation (Aries, Leo, Sagittarius) and are favored for fruiting and seed crops such as tomatoes, beans, and grain.

Thun's system, carried forward today by the Maria Thun calendar published annually by her son Matthias Thun, layers several rhythms at once. Beyond the roughly 27.3-day sidereal cycle of the moon through the zodiac, it tracks the moon's ascending and descending arc (its changing height in the sky across about a fortnight), perigee and apogee, the lunar nodes, and planetary oppositions and conjunctions. Practitioners are told to avoid sowing or transplanting during nodes and eclipses, treated as unfavorable moments, and to spray the horn-silica preparation (501) on mornings of ascending or fruit-favorable periods to strengthen the cosmic, light-related qualities of the crop. The Biodynamic Association notes that the calendar is a guide rather than an absolute rule, and that weather and soil readiness still take precedence over the stars on any given day.

What the evidence shows

Faithfully describing the system is one thing; testing it is another, and here the record is honest and mixed. The lunar-rhythm and zodiacal claims have not found support in peer-reviewed agronomy. The most cited attempt to reproduce Thun's results, by Hartmut Spiess at the Institute for Biodynamic Research in Darmstadt during the 1970s and 1980s, ran multi-year trials on cereals and root crops and concluded that any lunar or sidereal effects were small, inconsistent, and swamped by ordinary variables such as soil moisture and sowing depth. A widely noted 2002 radish study by Jan Graham Zander and colleagues, set up specifically to test Thun's root-day claim, found no statistically significant advantage to sowing on the prescribed days. Reviews of the wider literature reach the same verdict: there is no reliable, replicated evidence that the position of the moon in the zodiac changes crop yield or quality.

This is the central tension a complete account of biodynamics has to hold. The cosmic calendar rests on Steiner's spiritual reading of nature and on Thun's field observations, not on a mechanism that physics or plant science recognizes, and controlled trials have not confirmed it. At the same time, the broader biodynamic and organic practices that usually travel with the calendar, such as composting, cover cropping, and reduced chemical input, do have measurable benefits for soil structure and biodiversity, documented for instance in the long-running DOK trial run in Switzerland since 1978 by the Research Institute of Organic Agriculture (FiBL). The calendar, in short, is best understood as a coherent cultural and philosophical practice that many growers find meaningful and orienting, rather than as an established agronomic technique. Practitioners who follow it report a closer, more attentive relationship to the rhythms of their land, which is itself part of what Steiner said he was after, even where the specific cosmic claims remain unproven.

History, Demeter Certification, and Today

Biodynamics did not begin with a manifesto. It began with worried farmers. In the early 1920s, growers across German-speaking Europe brought Rudolf Steiner a cluster of practical complaints: degenerating seed-strains, crops that could no longer be reseeded year after year from a farmer's own grain, and spreading animal disease. Ehrenfried Pfeiffer, the young chemist who would become the method's chief popularizer, recorded the questions in his preface to the published course. In 1922 and 1923 the farmer Ernst Stegemann and his colleagues asked "what can be done to check this decline and to improve the quality of seed and nutrition?" A second group, including the veterinarian Dr. Joseph Werr and the physician Dr. Eugen Kolisko, came worried about sterility and foot-and-mouth disease. A third set of problems arrived from Count Carl von Keyserlingk, an estate owner in Silesia.

The Koberwitz course, June 1924

Keyserlingk was the one who finally forced the issue. According to Pfeiffer, Steiner was "already overwhelmed with work, tours and lectures" and "put off his decision from week to week," so the Count "dispatched his nephew to Dornach, with orders to camp on Dr. Steiner's doorstep and refuse to leave without a definite commitment for the course." The commitment was given. The result was the eight-lecture cycle that founded the field: held, in Pfeiffer's words, "from June 7 to 16, 1924, in the hospitable home of Count and Countess Keyserlingk at Koberwitz, near Breslau." Koberwitz is today Kobierzyce, in Poland; Breslau is now Wroclaw. The course was followed by further lectures in Breslau, "among them the famous 'Address to Youth.'" Pfeiffer notes the cycle "was attended by some sixty persons," restricted to farmers, gardeners, and scientists who combined practical experience with an anthroposophical background.

Steiner himself did not coin the movement's name. As Pfeiffer is careful to state, "the name, 'Bio-Dynamic Agricultural Method,' did not originate with Dr. Steiner, but with the experimental circle concerned with the practical application of the new direction of thought." That body, the Experimental Circle of Anthroposophical Farmers (Versuchsring), was formed soon after Koberwitz to test Steiner's indications under field conditions and to standardize the preparations. Steiner died in March 1925, less than a year after delivering the course, so the entire practical edifice of biodynamics was built by his followers rather than by him. The same broad anthroposophical impulse gave rise in those years to its sister movement in medicine, the subject of our pillar on anthroposophic medicine, and to the social philosophy described in our guide to social threefolding.

Pfeiffer and the spread to America

Pfeiffer was central to that building. He had made the very first batch of the horn manure preparation (500) with Guenther Wachsmuth and helped dig it up in Steiner's presence in "the early summer of 1924," an event he called "the birth-hour of a world-wide agricultural movement." Through the 1920s and 1930s he refined the preparations and answered the standard objection of the era. As Pfeiffer recorded, "in the period from 1924-1930 the bio-dynamic preparations were ridiculed 'because plants cannot possibly be influenced by high dilutions.'" In the late 1930s Pfeiffer carried the method across the Atlantic, lecturing in Britain and the United States and establishing biodynamic work at the Threefold Farm in Spring Valley, New York, and later in Pennsylvania. His 1938 book Bio-Dynamic Farming and Gardening became the standard English-language introduction and seeded the American movement that continues through the Josephine Porter Institute, which makes and distributes the preparations today.

Demeter: the oldest ecological certification

To protect the quality claims of biodynamic produce, the movement created a certification mark named for the Greek goddess of the harvest. According to Demeter International, the Demeter symbol was registered as a trademark in 1928, which makes it, in the organization's own account, the oldest ecological certification scheme in the world, predating modern organic labeling by decades. The German agronomist Erhard Bartsch, who also directed the Experimental Circle, administered the early mark; the name was chosen jointly with the chemist Franz Dreidax, who developed its quality-control standards.

The Demeter standard is deliberately stricter than baseline organic. Demeter USA states that its Farm Standard "builds off of the organic requirements under the National Organic Program, but is much more extensive, with stricter requirements around imported fertility, greater emphasis on integrated pest and weed management, and in depth specifications around water conservation and biodiversity." Two features set it apart. First, it is a whole-farm certification aimed at a "self-contained ecosystem," and, as Demeter USA notes, "field-by-field certification is not allowed," so a grower cannot certify a single biodynamic block while farming the rest conventionally. Second, the nine biodynamic preparations are mandatory: their use "is a requirement of the Farm Standard." A farm must therefore meet organic rules and then add the biodynamic layer on top, which is why Demeter-certified acreage remains a small fraction of certified-organic acreage worldwide.

Biodynamics today

A century after Koberwitz, the method has measurable global scale. Marking its 2024 centenary, Demeter International reported "more than 7,000 Demeter certified farms and 255,000 hectares of land in 62 countries around the world." The Biodynamic Association in the United States and the Biodynamic Association in the United Kingdom promote the practice regionally, while Maria Thun's annual sowing and planting calendar, published continuously since 1962 and still issued by her family, remains the movement's best-known guide to working with lunar and zodiacal rhythms.

The method's most visible commercial foothold is wine. Biodynamic viticulture has been adopted by a roster of internationally rated estates, and many wear Demeter or the wine-specific Biodyvin certification as a quality signal. In Burgundy, Domaine Leflaive converted under Anne-Claude Leflaive and farmed its entire Cote de Beaune holding biodynamically by 1998. In Alsace, Olivier Humbrecht, France's first Master of Wine, brought Domaine Zind-Humbrecht to full biodynamic certification in 2002. Austria's Nikolaihof, in the Wachau, has been Demeter-certified since 1998. In California, Benziger Family Winery in Sonoma certified its estate vineyards biodynamic in 1998. These producers do not prove Steiner's cosmology, and the certification says nothing about flavor on its own, but they demonstrate that biodynamic protocols are compatible with agriculture at the highest commercial tier. Whether the preparations and the calendar add anything beyond rigorous organic management remains, as the next section discusses, largely outside the reach of peer-reviewed confirmation, even as the soil-health and biodiversity gains of the underlying organic practice are better supported.

Evidence and Reception, Stated Fairly

Biodynamic agriculture occupies an unusual position in the history of farming. It is, by date, the first organized organic movement: Rudolf Steiner gave his Agriculture Course at Koberwitz in June 1924, two decades before Lord Northbourne coined "organic farming" in Look to the Land (1940) and Sir Albert Howard published An Agricultural Testament (1940). Steiner's pupil Ehrenfried Pfeiffer carried the method to Britain and the United States and wrote its first practical manual, Bio-Dynamic Farming and Gardening (1938). Any fair assessment has to separate two very different things bundled inside that legacy: a set of land-management practices that mainstream agronomy now broadly endorses, and a set of cosmic and astrological claims that remain unsupported by controlled evidence.

What the soil-science evidence actually shows

The most-cited data point is the DOK trial, a side-by-side field experiment running near Therwil, Switzerland since 1978, managed by the Research Institute of Organic Agriculture (FiBL) and Agroscope. DOK compares biodynamic ("D"), bioorganic ("O"), and conventional ("K", from German konventionell) systems on the same soil. Across more than four decades, the organic and biodynamic plots have shown higher soil microbial biomass and activity, greater earthworm abundance, better aggregate stability, and roughly 20 to 40 percent lower crop yields than conventional plots receiving synthetic inputs. A widely cited summary by Paul Mäder and colleagues appeared in Science in 2002 ("Soil Fertility and Biodiversity in Organic Farming").

The honest reading of DOK is that the soil-health and biodiversity gains track the organic management as a whole: compost, manure, legume rotations, and the absence of synthetic pesticides and soluble fertilizer. The trial was not designed to isolate the effect of the biodynamic preparations themselves, and the biodynamic and bioorganic systems perform similarly on most soil measures. So DOK is strong evidence for organic methods and weak evidence, at best, for anything specific to Steiner's horn or compost preparations. Reviews of biodiversity on organic and biodynamic farms, such as the meta-analyses by Bengtsson and by Tuck, reach a parallel conclusion: farming without synthetic agrochemicals tends to support more species, whatever the philosophy attached.

The pseudoscience criticism, stated fairly

The criticism, voiced by Linda Chalker-Scott of Washington State University and by science writers reviewing the field, targets the preparations and the sowing calendar, not the composting. Preparation 500 asks the farmer to fill a cow horn with manure, bury it over winter, then stir a small quantity in water for an hour and spray it across hectares of land; preparations 502 through 507 use yarrow, chamomile, nettle, oak bark, dandelion, and valerian, several sheathed in animal organs. The objection is straightforward: the dilutions are extreme, the proposed "cosmic" and "etheric" mechanisms have no basis in chemistry or physics, and Maria Thun's planting calendar relies on the zodiac, which has no demonstrated effect on plant growth. Steiner himself framed the work in those terms, describing the course as an introduction to "spiritual, cosmic forces and making them effective again in the plant world." Controlled trials of the preparations have produced inconsistent and mostly null results; where biodynamic plots outperform conventional ones, the gain is generally attributable to the organic regime rather than to the preparations.

The considered response from practitioners is twofold. First, biodynamics is presented as a working farm method judged by results in the field, in the tradition Pfeiffer described of farmers who "understood only partially or not at all, but immediately put suggestions into practice." Second, the preparations are used in homeopathic-scale quantities precisely because the claim is one of formative influence on living processes, not bulk nutrient supply, a claim that current science has no instrument to confirm and that therefore sits outside, rather than against, the peer-reviewed literature. A reader can accept the documented soil and biodiversity benefits of the organic core while remaining unconvinced by the astronomical and preparation-specific theory. That distinction is the fairest summary the evidence allows, and it is the one we hold to in our companion entry on the broader practice of biodynamic agriculture.

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