Understanding the biodynamic garden calendar: root, leaf, flower and fruit days

Understanding the biodynamic garden calendar: root, leaf, flower and fruit days

Sowing on a "root" day, planting under a descending moon, skipping lunar nodes and perigee… The biodynamic calendar can sound esoteric; it is actually built on simple, observable astronomy. Here is how to read it — and how to use it without overcomplicating your gardening.

Contents

• Where does the biodynamic calendar come from?
• The four types of days
• Ascending or descending moon: the cycle that changes everything
• Unfavourable periods: nodes, perigee, apogee
• What about the famous "preparations"?
• How to use it in the vegetable garden
• FAQ

Where does the biodynamic calendar come from?

Biodynamics grew out of a series of lectures on agriculture given by Rudolf Steiner in 1924, considered the founding act of organic farming. The "calendar" side was developed a few decades later by Maria Thun, who ran comparative sowing trials for over thirty years according to the moon's position — and turned them into a sowing and planting calendar republished every year since.

An honest clarification: the day calendar is a gardening tradition, not established science — lunar effects on plants are not proven in the academic sense. Generations of gardeners have used it as an organising framework: each vegetable has its day, each task its week. That is the spirit in which we offer it.

The four types of days

Every day, the moon passes through a zodiac constellation. Maria Thun associated each constellation with an element, and therefore with a plant organ to favour:

• Root days — moon in Taurus, Virgo or Capricorn (Earth element). Sowing and tending root vegetables: carrots, beetroot, radishes, garlic, shallots; planting and lifting tubers.
• Leaf days — moon in Cancer, Scorpio or Pisces (Water element). Leaf vegetables: lamb's lettuce, spinach, lettuces, cabbages, leeks; watering and harvesting greens.
• Flower days — moon in Gemini, Libra or Aquarius (Air element). Flowering plants: ornamentals, flowering herbs, artichokes and cauliflowers.
• Seed and fruit days — moon in Aries, Leo or Sagittarius (Fire element). Fruit vegetables: tomatoes, squashes; harvesting storage fruit and sowing seed crops. A note on a real divergence between traditions: broad beans and peas are classed as flower days in the French tradition and as fruit days in Maria Thun's calendar — both conventions exist.

The right mindset: a "root" day is not intrinsically better than another — it simply indicates which part of the garden deserves your time.

Ascending or descending moon: the cycle that changes everything

Watch out for the classic confusion: ascending/descending has nothing to do with waxing/waning.

• Waxing / waning moon = illumination: the moon grows towards full moon, then shrinks towards new moon. A cycle of about 29.5 days.
• Ascending / descending moon = the moon's height in the sky, which rises day after day for ~13 days (ascending) then falls (descending). Watch it at the same hour several evenings running: it climbs, or it sinks.

Tradition holds that under an ascending moon, sap rises into the upper parts: the time for sowing, grafting and pruning fruit trees — also the right moment to harvest fruit, leaves and fruit vegetables. Under a descending moon, sap flows back towards the roots: the time for planting out, cuttings, soil work, and harvesting root vegetables and bulbs for storage (garlic, potatoes). For storage, the day matching the crop matters most of all: onions on a root day, apples on a fruit day.

Unfavourable periods: nodes, perigee, apogee

The calendar also flags windows where it is best to leave the garden alone:

• Lunar nodes — the two points where the moon's orbit crosses the ecliptic, roughly twice a month. The French tradition advises against gardening for about five hours either side of the crossing; some calendars widen the caution to 12-24 h.
• Perigee — the moon at its closest to Earth. Traditional caution window: about 24 h either side of the exact moment; some traditions associate it with less flavoursome harvests and hindered germination.
• Apogee — the moon at its furthest. Traditional caution ~48 h around the instant; a real divergence: other traditions actually judge apogee favourable for some harvests (potatoes, fruit).
• New moon — sap reputedly at its lowest; a rest day in most calendars, with a few exceptions depending on the tradition (grafting).
• Full moon — conversely, the reputed peak of growth force: the French tradition advises sowing two or three days before the exact instant rather than on the day itself; other traditions add caution when a full moon coincides with a perigee or a node.

Our weekly agendas flag these windows with the real astronomical time (London time, GMT).

What about the famous "preparations"?

Biodynamics proper goes further than the calendar: it uses specific preparations — horn manure (preparation 500) dynamised and sprayed on the soil, horn silica (501) on the upper parts, and plant-based compost preparations (yarrow, chamomile, nettle, oak bark, dandelion, valerian). These belong to Demeter-certified biodynamic farms; for the family vegetable garden, the day calendar is more than enough to start — preparations belong to a whole-farm approach.

How to use it in the garden, simply

• The minimal reflex: plant under a descending moon, sow and harvest under an ascending moon.
• The full reflex: add the day type — garlic on a root day, lamb's lettuce on a leaf day, tomatoes on a fruit day.
• Safety: skip nodes, perigee, apogee and new moon day.
• Every Saturday, check the week's agenda in our Garden calendar section — the calculations are done for you, task by task.

FAQ

Is the biodynamic calendar proven?

No — no established scientific evidence validates constellation effects on sowing. It is a tradition for organising garden work, used successfully for generations. Our advice: treat it as a framework, not an obligation — a rainy Saturday on a root day beats a perfect flower day spent indoors.

What is the difference between a lunar and a biodynamic calendar?

The "lunar calendar" also covers the phases (waxing/waning); the "biodynamic calendar" specifically means Maria Thun's constellation day method (root, leaf, flower, fruit) with ascending/descending moon and unfavourable periods. The two complement each other — our lunar garden calendar combines both.

And for indoor sowing?

Indoors, the cycles matter less than light and warmth — but if you enjoy the approach, sow your seeds on the matching day (tomatoes on a fruit day, basil on a leaf day). The Germie germination kit gets most seeds sprouting in days, whatever the sky.

Method note: the times in our agendas are computed from real astronomical positions (London time, GMT). The gardening recommendations belong to the lunar-calendar tradition, checked against established biodynamic gardening practice — this is not established science.