In the early days of farming, it was also during the era of Moon Worshiping. Most likely due to observing the relationship between the moon and tides that made early man believe it was the source of all moisture. Everything from sap of plants, blood of all living creatures, to everything liquid all seemed to be controlled by the moon.
Also, Man's first calendar was as periods of time reckoned by the moon. So it was a natural thing to use the changes or phases of the moon to do certain things. Many farmers today still follow those early superstitions.
Planting in "the light of the moon" means in the time between new and the full moon. Planting in the "dark of the moon" refers to the period between full and new moon. However, scientist have a different meaning for these terms. They think that light phase of the moon as the time when the moon is above the horizon from dusk to midnight; and the dark phase is from midnight to dawn. Tests so far by many, haven't been able to determine if it made much difference in size. I referred to one study in particular: http://www.undeceivingourselves.com/S-plan.htm
The full moons of September and October are known as "The Harvest Moons". Because of their brilliance, early societies looked to it as a special gift from good spirits. The truth is that the moon is at a smaller angle with the horizon, and so it is more radiant. In the Southern Hemisphere, this bright moon takes place during March and April.
