We came across some interesting details about the Mitzva of ערלה in our Talmud class today. It is well known that we must wait three years before the fruit of a newly planted tree may be eaten. What is not so well known is how to calculate these three years. The Halacha is that the counting goes from Rosh Hashana. This means that as long as a tree was planted thirty days before Rosh Hashana, it counts as one year. Therefore, the shortest amount of time to eat from the fruit of a new tree would be twenty five months. The longest amount of time would theoretically be thirty six months and twenty nine days. This thirty days before Rosh Hashana rule also applies to the year of Shmitta. If planting took place thirty or more days before Rosh Hashana that would begin the Shmitta year, the planting would be considered a sixth year planting. If planting took place less than thirty days before, it would be viewed as seventh year planting, which is forbidden. In such a case, whatever was planted would have to be uprooted. Interesting Halacha.