Biodynamics has its own unique toolbox.
Some of the tools are familiar to organic growers: compost, manure, herbs, minerals, soil care, biodiversity, seasonal observation, and healthy plant growth.
Others are more unusual.
Biodynamic farming and gardening uses a small group of special preparations made from herbs, minerals, animal manures, and animal sheaths. These preparations are used in tiny amounts and are applied to compost, soil, or plants. They are not used like normal fertilisers. They are used more like biological or energetic catalysts.
In biodynamic thinking, the preparations help organise, enliven, and balance the processes of soil, compost, plant growth, and the wider farm ecosystem.
To someone new to biodynamics, this can sound strange. Cow horns, yarrow flowers, oak bark, dandelions, valerian, nettles, and horsetail all have specific roles. But once you see them as part of a symbolic and practical system, the pattern becomes clearer.
The biodynamic toolbox is not random. Each preparation is connected to a particular plant, mineral, animal material, season, and process in nature.
What Are Biodynamic Preparations?
Biodynamic preparations are specially made natural substances used in biodynamic farming and gardening.
The classic biodynamic preparations are numbered 500 to 508.
They are usually grouped into three main types:
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Field spray preparations These are sprayed onto soil or plants.
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Compost preparations These are added to compost heaps, manure, liquid manures, or composting systems.
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Plant health preparation This is usually associated with horsetail and is used in relation to fungal pressure and moisture balance.
The Biodynamic Association in the UK lists the nine classic biodynamic preparations as horn manure, horn silica, yarrow, chamomile, stinging nettle, oak bark, dandelion, valerian, and horsetail. Biodynamic organisations such as Demeter and the Biodynamic Association describe these preparations as being used to support soil life, plant growth, compost quality, and the vitality of the farm organism.
Biodynamic Preparations Are Not Ordinary Fertilisers
One important thing to understand is that biodynamic preparations are not used like standard fertilisers.
A fertiliser usually works by adding measurable nutrients such as nitrogen, phosphorus, or potassium.
Biodynamic preparations are used in very small quantities. Their role is not simply to “feed” plants directly. Instead, biodynamic growers believe they help stimulate, balance, or guide living processes.
That might include:
- humus formation
- root development
- compost transformation
- nutrient cycling
- plant vitality
- microbial activity
- soil structure
- plant resilience
- balance between growth and ripening
- relationship between soil, plants, animals, and the wider environment
In this sense, biodynamic preparations are best understood as part of a whole-system approach.
They sit alongside composting, animal integration, soil cover, biodiversity, crop rotation, hedgerows, careful timing, and deep observation.
The Core Biodynamic Toolbox
The classic biodynamic preparations are:
| Number | Name | Main Material | Main Use |
|---|---|---|---|
| 500 | Horn Manure | Cow manure | Soil spray |
| 501 | Horn Silica | Quartz/silica | Plant spray |
| 502 | Yarrow | Yarrow flowers | Compost preparation |
| 503 | Chamomile | Chamomile flowers | Compost preparation |
| 504 | Stinging Nettle | Nettle plant | Compost preparation |
| 505 | Oak Bark | Oak bark | Compost preparation |
| 506 | Dandelion | Dandelion flowers | Compost preparation |
| 507 | Valerian | Valerian flowers | Compost preparation |
| 508 | Horsetail | Horsetail plant | Plant health spray/tea |
Each one has its own place in the system.
500: Horn Manure
What it is
Horn manure, also known as Preparation 500, is one of the most important biodynamic preparations.
It is made from cow manure placed inside a cow horn and buried in the soil over winter. After several months underground, the transformed manure is dug up, stirred into water, and sprayed onto the soil.
What it is believed to do
In biodynamics, horn manure is connected with the life of the soil.
It is believed to:
- stimulate soil life
- support root growth
- encourage humus formation
- strengthen the relationship between plant roots and soil
- improve soil structure
- help plants connect more deeply with the earth
- support microbial activity
Horn manure is usually applied to the soil, often in the afternoon or evening, when the intention is to encourage root and soil activity.
Soil and ecosystem role
In practical soil terms, horn manure represents the biodynamic focus on the underground world.
It is about roots, humus, earthworms, microbes, moisture, and the living fertility of the soil.
It says: start with the soil.
Healthy growth begins below ground.
501: Horn Silica
What it is
Horn silica, also known as Preparation 501, is made from finely ground quartz or silica placed inside a cow horn and buried in the soil over summer.
It is later mixed with water and sprayed in a very fine mist over plants.
What it is believed to do
Horn silica is considered the companion to horn manure.
Where horn manure is associated with soil, roots, and earth processes, horn silica is associated with light, leaves, ripening, and plant form.
It is believed to:
- support photosynthesis
- improve plant structure
- enhance ripening
- strengthen flavour and quality
- help plants use light more effectively
- bring clarity and definition to plant growth
- improve crop resilience when used carefully
Soil and ecosystem role
Horn silica is not mainly a soil preparation. It is more connected with the above-ground parts of the plant.
In biodynamic language, horn manure and horn silica work as a polarity:
- 500 supports earth and root processes
- 501 supports light and leaf processes
Together, they are used to balance plant growth between the soil below and the light above.
502: Yarrow
What it is
Yarrow, also known as Preparation 502, is made from the flowers of yarrow, usually Achillea millefolium.
Traditionally, the yarrow flowers are placed inside a stag’s bladder and exposed to seasonal influences before being buried and later used in compost.
What it is believed to do
Yarrow is associated with subtle nutrient processes in the compost heap.
Biodynamic growers traditionally connect yarrow with:
- sulphur processes
- potassium activity
- trace mineral organisation
- compost vitality
- resilience
- the ability of plants to make good use of nutrients
Yarrow is used in very small amounts in compost, where it is believed to help organise nutrient movement and improve the quality of the finished compost.
Soil and ecosystem role
Yarrow itself is a tough, aromatic, flowering plant that attracts insects and grows in a wide range of conditions.
In the biodynamic toolbox, yarrow represents fine-tuning.
It is not about adding bulk fertility. It is about helping the compost heap become more ordered, balanced, and alive.
In a wider ecosystem, yarrow is also valuable for pollinators and beneficial insects, so it earns its keep both symbolically and practically.
503: Chamomile
What it is
Chamomile, also known as Preparation 503, is made from chamomile flowers, commonly Matricaria chamomilla or Matricaria recutita.
Traditionally, the flowers are placed inside the intestine of a cow and buried in the soil over winter before being added to compost.
What it is believed to do
Chamomile is often associated with calming, stabilising, and harmonising processes.
In biodynamic composting, it is believed to:
- support stable decomposition
- help regulate nitrogen
- encourage balanced breakdown of organic matter
- reduce nutrient losses
- support calcium-related processes
- help compost become more refined and soil-like
Soil and ecosystem role
Chamomile is a gentle but powerful plant in the biodynamic imagination.
In compost, it is seen as helping prevent chaotic decomposition. Rather than organic matter simply rotting down, chamomile is believed to support a more ordered transformation into humus.
For soil, that means compost that is not just broken-down waste, but a more stable, living amendment.
504: Stinging Nettle
What it is
Stinging nettle, also known as Preparation 504, is made from the whole nettle plant, usually Urtica dioica.
Unlike several other biodynamic compost preparations, nettle is not usually placed inside an animal sheath. It is buried in the soil for a long period, often surrounded by a protective layer such as peat or soil.
What it is believed to do
Nettle is one of the great soil plants.
In biodynamics, nettle is believed to:
- stimulate soil vitality
- support iron processes
- strengthen compost activity
- bring order and intelligence to the compost heap
- support nitrogen transformation
- improve the relationship between soil and plant growth
- encourage balance rather than excessive lushness
Soil and ecosystem role
Nettles are mineral-rich, fast-growing, and strongly connected with fertility.
They often grow where soil is rich in nitrogen and organic matter. They are also important wildlife plants, especially for butterflies and insects.
In the biodynamic toolbox, nettle acts almost like a compost regulator.
It is believed to help the compost heap become more sensitive, balanced, and alive.
Nettle is the compost heap’s stern but brilliant teacher. Slightly prickly, absolutely useful.
505: Oak Bark
What it is
Oak bark, also known as Preparation 505, is made from the bark of oak, often Quercus robur in Europe.
Traditionally, the bark is placed inside the skull of a domestic animal and kept in a moist, earthy place before being added to compost.
What it is believed to do
Oak bark is strongly associated with calcium and structure.
In biodynamics, it is believed to:
- support calcium processes
- help strengthen plants
- improve resistance to disease
- bring structure and firmness to compost
- help regulate excessive growth
- support plant health in damp or disease-prone conditions
Soil and ecosystem role
Oak trees are long-lived, strong, and deeply connected with woodland ecosystems.
Oak bark contains tannins and minerals and has a long traditional association with strength, protection, and preservation.
In compost, oak bark preparation is believed to bring firmness and disease resistance into the system.
For the soil ecosystem, it represents structure, resilience, and the ability to hold form.
506: Dandelion
What it is
Dandelion, also known as Preparation 506, is made from dandelion flowers, usually Taraxacum officinale.
Traditionally, the flowers are placed in the mesentery of a cow and buried over winter before being used in compost.
What it is believed to do
Dandelion is associated with silica, potassium, and the intelligent movement of nutrients.
In biodynamics, dandelion is believed to:
- help plants access what they need from the soil
- support silica processes
- aid potassium activity
- improve nutrient sensitivity
- support balanced plant growth
- connect the plant more intelligently with its environment
Soil and ecosystem role
Dandelions are deep-rooted, resilient plants that can draw minerals from below the surface. Their flowers feed pollinators early in the season, and their roots help open compacted soil.
In the biodynamic toolbox, dandelion is associated with sensitivity.
It is believed to help the compost and soil become more responsive, so plants can better interact with the nutrients and forces around them.
The humble dandelion is doing far more than annoying lawn perfectionists.
507: Valerian
What it is
Valerian, also known as Preparation 507, is made from the flowers of Valeriana officinalis.
The flowers are extracted into water, and the liquid is used in compost or sprayed over the compost heap.
What it is believed to do
Valerian is often associated with warmth and phosphorus processes.
In biodynamics, valerian is believed to:
- stimulate compost activity
- support warmth in the compost heap
- help with phosphorus processes
- protect compost and plants from stress
- bring a finishing influence to the compost preparations
- support flowering and vitality
Valerian is usually used as a liquid preparation and sprinkled or sprayed over the compost heap after the other compost preparations have been inserted.
Soil and ecosystem role
Valerian is a flowering herb with a strong traditional association with calming and healing.
In biodynamic composting, it is often seen as a kind of protective warmth-giver.
It helps complete the compost preparation set and is believed to encourage the heap to work as a living whole.
508: Horsetail
What it is
Horsetail, also known as Preparation 508, is made from Equisetum arvense.
It is usually prepared as a tea or decoction and sprayed onto plants or soil.
What it is believed to do
Horsetail is rich in silica and is traditionally associated with moisture balance and fungal pressure.
In biodynamic practice, horsetail is believed to:
- help reduce fungal problems
- support plant resilience in damp conditions
- balance excess watery growth
- strengthen plant surfaces
- support silica-related processes
- help plants cope with mildew, mould, and fungal pressure
Soil and ecosystem role
Horsetail is an ancient plant, often found in damp or compacted places. Its high silica content makes it important in many traditional plant preparations.
In the biodynamic toolbox, horsetail is often used when conditions are too wet, too fungal, or too heavy.
It is not usually considered one of the compost preparations. It is more often used as a plant health spray.
The Six Compost Preparations: 502-507
The six compost preparations are:
- yarrow
- chamomile
- stinging nettle
- oak bark
- dandelion
- valerian
These are added to compost in tiny amounts.
In biodynamic thinking, compost is not simply a pile of rotting material. It is a place where organic matter is transformed into living fertility.
The compost preparations are believed to help guide this transformation.
They are associated with the organisation of nutrients such as:
- nitrogen
- potassium
- calcium
- phosphorus
- sulphur
- silica
- iron
- trace minerals
Each preparation is believed to bring a different quality.
Together, they are used to help compost become more balanced, stable, humus-rich, and biologically alive.
The Two Main Field Sprays: 500 and 501
The two main field sprays are:
- horn manure
- horn silica
These are often seen as the central pair of biodynamic field preparations.
Horn Manure: Earthward
Horn manure is connected with:
- soil
- roots
- humus
- earthworms
- microbial life
- moisture
- grounding
- fertility
It is sprayed onto the soil.
Horn Silica: Skyward
Horn silica is connected with:
- light
- leaves
- flowering
- ripening
- plant form
- photosynthesis
- flavour
- quality
It is sprayed over the growing plant.
Together, they represent one of the key biodynamic ideas: plant health depends on the relationship between earth and cosmos, root and leaf, soil and light.
Why Are Animal Materials Used?
One of the most unusual parts of biodynamic preparations is the use of animal materials.
These can include:
- cow horns
- stag bladder
- cow intestine
- animal skull
- cow mesentery
To modern eyes, this can seem odd or uncomfortable.
In biodynamic thinking, these animal materials are not simply containers. They are understood as sheaths or organs that help transform the plant, mineral, or manure material during the preparation process.
The preparation is exposed to earth, season, moisture, warmth, cold, and time. The animal sheath is believed to help focus or mediate these influences.
This is one of the more spiritual and symbolic aspects of biodynamics.
Some growers accept it fully. Some are curious but cautious. Others focus more on the composting, soil, and ecological side of biodynamics.
It is worth being honest: this part of biodynamics is different from mainstream organic gardening.
The Herbs and Natural Materials in the Biodynamic Toolbox
Here is a simple guide to the main herbs and natural materials used in the biodynamic preparations.
| Material | Preparation | Biodynamic Association |
|---|---|---|
| Cow manure | 500 | Soil life, roots, humus |
| Quartz/silica | 501 | Light, ripening, plant form |
| Yarrow | 502 | Potassium, sulphur, nutrient organisation |
| Chamomile | 503 | Nitrogen stability, calcium, balanced decomposition |
| Stinging nettle | 504 | Iron, soil vitality, compost regulation |
| Oak bark | 505 | Calcium, structure, disease resistance |
| Dandelion | 506 | Silica, potassium, nutrient sensitivity |
| Valerian | 507 | Phosphorus, warmth, compost protection |
| Horsetail | 508 | Silica, fungal balance, moisture regulation |
This table gives a simple overview, but biodynamic growers usually see these materials as more than their chemical parts.
They are understood through their growth habits, seasonal rhythms, medicinal qualities, ecological roles, and relationship to the whole farm organism.
Yarrow in the Ecosystem
Yarrow is a hardy perennial with feathery leaves and flat clusters of small flowers.
In the garden or farm ecosystem, it can:
- attract pollinators
- support beneficial insects
- grow in poor soils
- tolerate drought
- add diversity to grassland or herbal leys
- contribute aromatic plant material to compost
In biodynamic preparations, yarrow is associated with subtle nutrient organisation, especially around potassium and sulphur.
Chamomile in the Ecosystem
Chamomile is a low-growing aromatic plant with daisy-like flowers.
In the ecosystem, it can:
- attract pollinators
- support beneficial insects
- add aromatic diversity
- grow in light, open soils
- contribute soft plant material to compost
In biodynamics, chamomile is associated with calming and stabilising the compost process, particularly around nitrogen and calcium.
Stinging Nettle in the Ecosystem
Stinging nettle is a vigorous, mineral-rich plant often found in fertile soils.
In the ecosystem, it can:
- feed butterfly caterpillars
- support insect life
- indicate nutrient-rich soil
- produce abundant biomass
- make useful liquid feed
- activate compost
- provide chop-and-drop mulch
In biodynamics, nettle is associated with vitality, iron, nitrogen transformation, and the inner organisation of the compost heap.
Oak Bark in the Ecosystem
Oak is one of the great keystone trees of temperate ecosystems.
In the ecosystem, oak can:
- support hundreds of insect species
- feed birds and mammals
- create leaf litter
- build fungal-rich woodland soil
- provide acorns
- form long-lived habitat
- support mycorrhizal fungi
In biodynamics, oak bark is associated with calcium, strength, structure, and disease resistance.
Dandelion in the Ecosystem
Dandelion is often dismissed as a weed, but it is a valuable ecological plant.
In the ecosystem, it can:
- provide early nectar and pollen
- support bees and pollinators
- open compacted soil with its taproot
- draw minerals from deeper soil layers
- grow in disturbed ground
- contribute leaves and flowers to compost
In biodynamics, dandelion is associated with nutrient sensitivity and helping plants make better use of what is available in the soil.
Valerian in the Ecosystem
Valerian is a tall flowering perennial with clusters of pale flowers and a strong scent.
In the ecosystem, it can:
- attract pollinators
- grow in damp areas
- add flowering diversity
- support beneficial insects
- contribute aromatic plant material
In biodynamics, valerian is associated with warmth, phosphorus, flowering, and a protective influence in compost.
Horsetail in the Ecosystem
Horsetail is an ancient, silica-rich plant often found in damp or compacted places.
In the ecosystem, it can:
- indicate wet or compacted soil
- accumulate silica
- stabilise damp ground
- provide mineral-rich plant material
In biodynamics, horsetail is associated with silica, fungal balance, and reducing excessive watery conditions.
It is often used as a spray when fungal diseases are a concern.
Cow Manure in Biodynamics
Cow manure is central to biodynamic fertility.
In a biodynamic system, manure is not treated as waste. It is a key part of the fertility cycle.
Cow manure can:
- feed soil microbes
- support composting
- build organic matter
- improve soil structure
- contribute nutrients
- connect livestock and land
- help close the farm fertility loop
Preparation 500 transforms cow manure through the horn and winter burial process. Biodynamic growers believe this intensifies its soil-supporting qualities.
Quartz and Silica in Biodynamics
Quartz is used in Preparation 501.
Silica is associated with:
- light
- structure
- plant surfaces
- leaf quality
- ripening
- resilience
- clarity of growth
In ordinary plant science, silicon is known to be beneficial for some plants, particularly in strengthening tissues and helping plants tolerate stress.
In biodynamics, silica also has a symbolic and energetic role. It is linked with the plant’s relationship to light and the wider cosmos.
Why These Particular Plants?
The biodynamic preparations use plants with strong medicinal, ecological, or mineral associations.
They are not chosen simply because they are common.
They each express a particular quality:
- yarrow is fine, aromatic, resilient, and insect-friendly
- chamomile is calming, aromatic, and stabilising
- nettle is vigorous, mineral-rich, and fertility-loving
- oak is strong, structured, and long-lived
- dandelion is deep-rooted, responsive, and mineral-seeking
- valerian is aromatic, flowering, and warmth-associated
- horsetail is ancient, silica-rich, and linked with moisture balance
In biodynamics, the character of the plant matters.
How it grows, where it grows, what it attracts, what minerals it relates to, and how it behaves in the landscape are all part of its meaning.
How the Preparations Are Used
Biodynamic preparations are usually used in very small quantities.
They may be:
- inserted into compost heaps
- stirred into water and sprayed
- added to liquid manures
- used in barrel compost
- applied to fields
- sprayed over crops
- used in gardens, orchards, vineyards, farms, and compost systems
The stirring process is also important in biodynamics.
Preparations are often stirred rhythmically in water, creating a vortex in one direction and then breaking it into chaos before stirring in the opposite direction. This is repeated for a period of time before spraying.
Biodynamic growers believe this stirring process helps enliven the water and distribute the preparation’s influence.
Biodynamic Preparations and the Soil Food Web
From a soil health perspective, the most accessible way to understand biodynamic preparations is to see them as part of a wider biological system.
They are used alongside:
- compost
- manure
- cover crops
- pasture
- animals
- trees
- hedgerows
- wild areas
- crop diversity
- living roots
- careful timing
- seasonal observation
The preparations are not meant to replace good land management.
They are used to support it.
A biodynamic farm still needs healthy compost, good soil cover, biodiversity, drainage, appropriate grazing, and careful cropping. The preparations are part of the system, not a shortcut around it.
Biodynamic Preparations and Biodiversity
Biodynamics places strong emphasis on the farm or garden as a living organism.
That means biodiversity matters.
The herbs in the biodynamic toolbox are not just preparation ingredients. Many are also valuable plants in their own right.
A biodynamic-inspired garden might grow:
- yarrow for insects and compost
- chamomile for flowers and aromatic diversity
- nettles in a wild corner for butterflies and liquid feed
- dandelions for early pollinators
- valerian for flowers and insect life
- horsetail where appropriate and controlled
- oak trees or oak leaf litter where space allows
The toolbox can therefore be understood in two ways:
- As formal biodynamic preparations.
- As a reminder that medicinal, mineral-rich, wild, and ecological plants have roles in soil and ecosystem health.
A Note on Certification and “Allowed” Preparations
If you are growing biodynamically for certification, always check the current standards of your certifying body, such as the Biodynamic Association Certification in the UK or Demeter in your region.
The classic preparations used in biodynamics are 500 to 508, but certification rules can include specific requirements around sourcing, making, storing, applying, and documenting preparation use.
For a home garden, allotment, or educational project, the biodynamic toolbox can be explored more gently.
For a certified farm or product, the standards matter.
A Balanced View
Biodynamic preparations are one of the most distinctive and debated parts of biodynamics.
Some people see them as deeply meaningful and effective. Some see them as symbolic. Some see them as spiritual. Some remain sceptical.
That is fine.
A balanced way to approach them is to say:
Biodynamic preparations are traditional biodynamic tools made from specific herbs, minerals, manures, and animal materials. They are used in tiny amounts to support compost, soil, plant health, and the whole farm organism. Their effects are understood within the biodynamic worldview, which combines practical agriculture, ecological observation, and spiritual ideas about nature.
You do not have to understand everything at once.
Biodynamics is less like reading a packet of fertiliser instructions and more like learning a language.
A slightly muddy, moon-watching, compost-loving language.
Final Thoughts
The biodynamic toolbox is small, but rich.
It contains cow manure, quartz, yarrow, chamomile, nettle, oak bark, dandelion, valerian, and horsetail.
Each material has a role. Each one is connected with a process in soil, compost, plants, or the wider ecosystem.
Horn manure speaks to roots, humus, and soil life. Horn silica speaks to light, leaves, and ripening. Yarrow supports subtle nutrient organisation. Chamomile brings stability to decomposition. Nettle brings vitality and regulation. Oak bark brings structure and resilience. Dandelion brings sensitivity to nutrients. Valerian brings warmth and protection. Horsetail brings silica and moisture balance.
Together, these preparations express the biodynamic idea that farming is not just about feeding crops.
It is about caring for living processes.
The soil is alive. The compost heap is alive. The farm is alive. And the grower’s role is to work with that life, not against it.