Guides
Gardening by the Moon: the traditional calendar, explained
Lunar gardening is one of the oldest uses of the almanac. Here is what the tradition actually prescribes — told as tradition, with what the science says alongside.
Two cycles the tradition follows
The gardening calendars rest on two different lunar cycles, and confusing them is the classic beginner's mistake. The first is the familiar cycle of phases — waxing from new to full, waning from full to new, in 29.53 days. The second is the Moon's height in the sky: over 27.3 days the Moon climbs higher day after day (a rising moon), then descends (a descending moon). A moon can be waxing and descending at once; the words are not synonyms.
Tradition ties sap movement to these cycles: sowing and grafting under a rising moon, when the sap is said to climb; planting, transplanting and pruning under a descending moon, when it is said to return to the roots. The waxing and waning phases, in the older farmers' tradition, separate what grows above ground from what grows below.
Leaf, fruit, flower and root days
The biodynamic calendars refine this further: as the Moon passes in front of the constellations of the zodiac, each day is classed as a leaf day (water signs), a fruit day (fire), a flower day (air) or a root day (earth) — and each is held favourable to the matching part of the plant. Lettuce on leaf days, tomatoes on fruit days, carrots on root days. In France, the reference calendars of this school — Michel Gros's Calendrier lunaire, the biodynamic movement's almanacs — sit on many potting-shed shelves, and gardeners check their apps against them.
What the science says
Honestly: controlled studies have not demonstrated a measurable effect of the Moon on germination or yield, and the sap-movement mechanism has no established physiological basis. What the calendar demonstrably provides is rhythm — a reason to be in the garden regularly, to plan the sowing, to observe. That is no small thing, and it is the almanac's oldest service. Plenilune's position is the same in the garden as in the sky: we give you the true cycle, the tradition told as tradition, and no predictions.
Questions
- What is the difference between a waxing moon and a rising moon?
- Waxing describes the phase: the lit fraction grows, from new moon to full, over about 15 days. Rising describes the Moon's path: day after day it culminates higher in the sky, over about 13.7 days. The two cycles run at different speeds, so every combination occurs — a moon can be waxing yet descending.
- When should I sow according to the tradition?
- The traditional rule of thumb: sow and graft under a rising moon; plant out, prune and harvest root crops under a descending moon. The biodynamic calendars add leaf, fruit, flower and root days according to the zodiac constellation the Moon crosses. Science has not confirmed an effect — treat it as rhythm and lore rather than law.
- Does the full moon really affect plants?
- No robust effect on germination or growth has been measured in controlled conditions. The gardening value of the lunar calendar is its regularity: it gets you into the garden on a rhythm, observing. We state the tradition faithfully and label it as tradition.