David in Normandy wrote:
My neighbour does his gardening based on the phase
of the moon. Such ancient superstition is common here in rural
communities.

I believe the basis of the moon phase planting (and planting out and
harvesting) is all related to the effect on water by the moon, as displayed
in the tides. It is meant to relate to the water being 'drawn up' more
easily at the times it's needed, etc.

Whether it works or not is another matter - I have considered trying to do a
blind trial test on it, but since I rarely get time to even plant, let alone
be told what I can plant when, it seems most unlikely I ever will.