The traditions behind the calendar

On honesty

The calendar labels its layers by what they do — Season, Moon phase, Today's group, Weather, Moon days — rather than by making causal claims. If you just want to know what to do today, nothing here asks you to believe anything. This page is for the reasoning behind the parts that are worth knowing about but that the calendar deliberately doesn't act on.

What actually drives the calendar

• Season — the 24 solar terms. Pure astronomy: tracks daylength, temperature and monsoon onset. Holds up.
• Moon phase — four work blocks of seven or eight days, hinged on the new moon, first quarter, full moon and last quarter. Waxing builds upward, leaf first then fruit; waning works downward, root first then storage. A work rhythm, not a mechanism, and keyed to the true astronomical instant rather than to any arithmetic lunar calendar. It replaced an older waxing/waning split, which said the same thing at half the resolution.
• Today's group — a four-part Root/Leaf/Flower/Fruit rotation. Weak as mechanism, strong as habit: it groups plants by organ, which really does group them by shared water needs, harvest method and pest profile.
• Weather — the only layer with real predictive power over today, so it overrules everything above it on physical grounds. A live forecast generates specific overrides: a high chance of rain will pause watering, feeding, and pruning; forecasted storms or frost will block transplanting; and peak heat shifts all major work to dawn or dusk.
• Moon days — the exact new moon and the exact full moon, and nothing else. The only two points in the phase cycle that stop work rather than shape it. No agronomic claim is made for them: a scheduled pause makes you look at the garden instead of working on it, which is where most pest and disease problems are first caught. Note that a moon day pauses work on elective grounds, so it will never authorize work that a weather override has blocked on physical grounds.
• วันพระ — in Thailand only, tracked on its own dates rather than the astronomy above. Thai lunar months are fixed 29- and 30-day counts with อธิกมาส and อธิกวาร intercalation, so ขึ้น ๑๕ ค่ำ lands a day or more from the true full moon often enough to be noticed. It is worth observing, but never as a substitute for the astronomy.

A tradition the calendar tracks but doesn't act on

Biodynamic gardening (following Maria Thun's work) reads the moon's position against the zodiac, not just its phase, and adds a few more markers: the moon crossing a lunar node, and its closest and farthest points from Earth (perigee and apogee). The claimed mechanisms are gravitational and energetic — that grafting near a node risks an eclipse-like disturbance, that growth begun near perigee comes in soft, and near apogee comes in weak. None of that is measured evidence the way the solar terms or the forecast are; it's recorded here as the reason some biodynamic calendars treat these as blackout windows, not as a claim this calendar makes. It doesn't affect any task, alert or verdict elsewhere in the app.