3,725. Rosh Hashana is the Start of the Year for Shemittah and Yoveil

Hilchos Shemittah v’Yoveil 4:9

The first of Tishrei (Rosh Hashana) is the start of the year when it comes to shemittah and yoveil. Regarding sixth-year produce that enters shemittah: grain, legumes and fruit that reached the stage of tithing before the Rosh Hashana of shemittah are permitted. Even if they are gathered during shemittah, they are like sixth-year produce in all ways. If they didn’t reach the tithing stage until after Rosh Hashana, then they’re considered shemittah produce.

Hilchos Shemittah v’Yoveil 4:10

The aftergrowth of grain and legumes may not be eaten and the fruit of trees must be eaten in the sanctity of shemittah.