Humans have ended short stories up associating many properties and various powers with the Moon, but what is the part of imagination and reality in all this?
full moon and new moon influence
The question of lunar influences is only folklore or belief: it can in fact be studied in practice. Of course, as with any scientific test, there are a few conditions: have many subjects (not a single tree or a person), observe for a long time (one cycle is not enough), eliminate effects without a direct link (to study the influence of the full moon on car accidents, we must first remove the well-known weekly variation), use the correct ephemeris (no, we cannot decide to have a 30-day lunar phase cycle instead of 29.53 because it is easier for the calculations), do not select the data to keep just those going in the direction of the desired effect, have replication on other data or by other researchers.
That being said, let's take a look at the different areas where the Moon short stories has been incriminated.
Weather: the role of tides
Does the Moon provide information about the atmosphere? Sometimes yes. The Moon will thus appear darker during total eclipses if the Earth's atmosphere contains a lot of dust. Around new moons, the ashen light will be brighter if the side of the Earth facing our satellite has more clouds. And if you see a halo around the full moon, it's because the atmosphere has ice crystals at altitude, in clouds called cirrostratus which sometimes, but not always, precede a worsening of the weather.
Everything that has just been described is in fact linked to the atmosphere, the Moon is in no way responsible, but is there a direct effect? Forget the tradition that the new moon heralds a change in the weather (since the phase is the same for all countries on Earth, this would imply a change in weather everywhere on the same day!). On the other hand, effects, although weak, of the Moon have been noticed for the weather at the Cerro Paranal observatory and for tropical rains: they are in fact linked to oceanic or atmospheric tides.
Another lunar reputation: it causes tsunami, earthquake, or eruption. Of course, terrestrial tides (yes, it's not just the water that rises, the ground too) knead the crust of our planet, while ocean tides, by moving large quantities of water, increase or decrease the pressure on this crust.
However, it is clear that the role of the Full Moon or New Moon is not gigantic, and in fact you already know this: we do not announce a big global catastrophe, widespread eruption and global earthquake, every full moon. At worst, it's possible that tides could bring the final straw to a fault nearing change or a volcano ready to erupt.
Gardening with the Moon
At the beginning, everything is based on a simple analogy: the shape of the Moon grows between the new moon and the full moon, so our satellite favors everything that needs to grow and it is a good time to sow. As time has passed, some have modified the initial tradition and "waxing Moon" sometimes refers to a Moon located further from the celestial equator (the projection of our terrestrial equator on the celestial sphere), which causes the Moon to change its height relative to the horizon, as the Sun is higher in the sky in summer and lower in winter.
The short stories here are based on a more “gravific” conception: a Moon located closer to the zenith “pulls” the plants upwards, pushing them to develop upright. This growing moon would therefore become favorable for what grows out of the ground (corn, for example) and unfavorable for what must be buried there (carrots, for example).
Finally, for about a century, still others have combined the growth of the Moon (in one or the other meaning) with its position in the sky, a moon/astrology mixture of sorts. However, it has been known and proven for centuries: soil quality, water supply, pest control, and weather are the most important factors for any good gardener to monitor. As a leaflet from the French National Horticultural Society points out, the New Moon doesn't have much to do with it.
(to be continued)
