3,563. When a Year Begins

Hilchos Maaser Sheini and Neta Revai 9:8

The first day of the month of Tishrei is the start of the year vis-à-vis orlah and neta revai. When it comes to these prohibitions, we start from the time the trees are planted. A “year” need not be from one Rosh Hashana to the next; rather, 30 days of a year are sufficient so long as the plant has taken root before those thirty days. The time for trees to take root is two weeks.

Hilchos Maaser Sheini and Neta Revai 9:9

Pursuant to the previous halacha, if someone plants a tree 44 days before Rosh Hashana, it’s as if the tree had been planted for the whole year. However, because of the prohibition of orlah, fruit from this tree is not permitted in the fourth year until Tu b’Shevat, which is “the new year for trees.”