Biodynamic gardening is a system of growing that treats the garden as a single living organism, with an emphasis on compost, soil health, biodiversity and timing work to the cycles of the moon and the seasons. It was developed in the 1920s from lectures by Rudolf Steiner, and it is practised by gardeners and farmers around the world, with its own certification system for farms. This guide explains what biodynamic gardening involves, how a home gardener might practise it, and — clearly and at the start — that biodynamic gardening is a traditional practice, not proven science. Many of its practices, such as composting, crop rotation and encouraging biodiversity, are sound gardening that any gardener would recognise. Other parts, such as its compost preparations and its claims about cosmic forces, are traditional beliefs that have not been established by scientific evidence. This guide labels those claims as traditional throughout, so you can judge the system for yourself.
The biodynamic view is that a garden is more than a collection of plants: it is a self-contained system in which soil, plants, animals and the gardener all play a part. A biodynamic garden aims to be as self-sufficient as possible, making its own compost, saving its own seed, and keeping animals such as chickens or bees where practical. It avoids synthetic fertilisers and pesticides, and it relies on compost, green manures, crop rotation and biodiversity to keep the soil fertile and the plants healthy. Those principles overlap heavily with organic gardening, and a gardener who composts, rotates crops and avoids chemicals is already practising much of what biodynamic gardening recommends, whether they call it biodynamic or not. Our composting basics guide covers composting, and our companion planting chart covers planting for biodiversity.
The biodynamic preparations
The most distinctive part of biodynamic gardening is its preparations: small quantities of herbal and mineral substances that are traditionally said to enliven the compost and the soil. The best known are the horn manure preparation, traditionally made by filling a cow horn with manure, burying it over winter, and then stirring a tiny amount into water and spraying it on the soil; and the horn silica preparation, traditionally made in a similar way with ground quartz, and sprayed on the leaves. There are also compost preparations made from yarrow, chamomile, stinging nettle, oak bark, dandelion and valerian, which are traditionally added to the compost heap in small amounts. These preparations are used in very small quantities — a handful stirred into a large volume of water — and they are traditionally said to stimulate soil life and plant growth.
It is important to be honest about these preparations: their effects have not been established by scientific evidence. Controlled trials comparing biodynamic preparations with ordinary compost have generally found that any differences are small and are explained by the compost and organic matter itself, not by the preparations. The preparations are harmless in the quantities used, and many biodynamic gardeners value them as a ritual that connects them to the garden and to the seasons, but they should not be presented as scientifically proven, and a gardener who composts well without them will have healthy soil. If you want to try them, use them as a traditional practice alongside good composting, not as a substitute for it. Check your local extension service if you want advice on composting and soil health in your area.
Lunar and cosmic timing
Biodynamic gardening also involves timing work to the cycles of the moon and, in some versions, to the positions of the planets. Sowing, planting, pruning and harvesting are traditionally timed to the moon's phases and to whether the moon is said to be in a root, leaf, flower or fruit period, according to an astronomical calendar. According to this traditional belief, root crops are sown on root days, leafy crops on leaf days, and so on. These claims are traditional beliefs, not scientifically established facts: there is no reliable evidence that the phase of the moon or the position of the planets affects how seeds germinate or plants grow. Our planting by moon phases guide explains lunar timing in detail, including the honest evidence position. A biodynamic gardener who follows the calendar often has a good garden, but that is most likely because the calendar gives them a regular routine of sowing and tending, not because of the moon or the planets. If you follow the calendar, use it as a planning rhythm, and let the frost date, the season and the seed packet decide when to sow — use the frost date calculator and the seed starting calculator for your local dates.
What a home gardener can take from biodynamics
A home gardener does not need to adopt the whole biodynamic system to benefit from its sound parts. Make good compost and use it generously, because compost is the foundation of healthy soil. Rotate crops so the same crop does not grow in the same place year after year. Grow a diversity of plants — vegetables, herbs, flowers and green manures — rather than a single crop, because diversity supports pollinators and beneficial insects. Keep the soil covered with mulch or green manures so it does not dry out or wash away. Avoid synthetic fertilisers and pesticides, and control pests with the organic-first methods in our guides, such as slug control and the pest identifier helper. Save seed from your best plants where practical, and keep a garden diary so you learn what works in your garden. These practices are good gardening by any standard, and they are the parts of biodynamics that any gardener can use with confidence.
If you want to go further, you can try the preparations and the lunar calendar as traditional practices, and judge them by how your garden does. Keep a record, compare a bed that follows the calendar with one that does not, and see for yourself whether you notice a difference. That is the honest way to test any gardening claim: in your own garden, with your own plants, over more than one season. And remember that the basics matter far more than any system: good soil, the right plant in the right place, water, light, spacing and timing by frost date and season. A garden that gets those right will thrive, whatever system its gardener follows.
Common mistakes
The most common mistakes in biodynamic gardening are treating the preparations and the lunar calendar as scientifically proven, using them as a substitute for good composting and soil care, and sowing at the wrong time of year because the calendar said so, while ignoring the frost date and the soil temperature. Another is spending a lot of time and money on preparations while neglecting the basics — watering, weeding, spacing and pest control. The fix is simple: take the sound parts of the system — compost, rotation, diversity, mulch, no chemicals — and treat the preparations and the lunar calendar as traditional practices to try if you enjoy them, not as proven methods. A garden built on good soil and good habits will do well, with or without the preparations.
Frequently asked questions
Is biodynamic gardening the same as organic gardening?
They overlap, but they are not the same. Both avoid synthetic fertilisers and pesticides, and both emphasise compost, rotation and biodiversity. Biodynamic gardening adds its own preparations and lunar and cosmic timing, which are traditional practices rather than scientifically established methods, and it has its own certification system for farms.
Do biodynamic preparations really work?
Their effects have not been established by scientific evidence. Controlled trials have generally found that any differences between biodynamic and ordinary organic gardening are small and are explained by the compost and organic matter itself, not by the preparations. The preparations are harmless in the quantities used, and many gardeners value them as a traditional ritual, but they should not be presented as scientifically proven.
What is the horn manure preparation?
It is the best-known biodynamic preparation, traditionally made by filling a cow horn with manure, burying it over winter, and then stirring a tiny amount of the contents into water and spraying it on the soil. It is traditionally said to stimulate soil life and plant growth. That claim is a traditional belief, not a scientifically established fact.
Can I practise biodynamic gardening in a small garden?
Yes. The sound parts — composting, crop rotation, diversity, mulching, avoiding chemicals — work in any size of garden, from a raised bed to a balcony. You can also try the preparations and the lunar calendar as traditional practices if you enjoy them. Our raised bed gardening and small space gardening guides cover the practical side of small gardens.
Is biodynamic gardening worth trying?
If you enjoy the philosophy, the rhythm and the ritual, it can be a rewarding way to garden, and its emphasis on compost, soil health and biodiversity is sound. Judge it by how your garden does, keep a record, and remember that good soil, water, light, spacing and timing by frost date matter far more than any system. If you want advice on soil and composting in your area, check your local extension service.