Corn Moon vs Harvest Moon

The September full Moon is usually known as the Full Corn Moon because it traditionally corresponds with the time of harvesting corn. It is also called the Barley Moon because this is the time to harvest and thresh ripened barley.

Often, the September Moon is also called the Harvest Moon, but this year the Harvest Moon occurs in October. The Harvest Moon is the Moon that falls nearest the autumnal equinox; this full Moon provides the most light at the time when it’s needed most—to complete the harvest!

Source: Almanac.com