1,153. To What Produce Does Chodosh Apply?
172:2 According to most authorities, the prohibition against eating new produce until after 16 Nisan also applies outside Israel on the Biblical level (as opposed to rabbinically). One must therefore closely supervise produce that may have been sown after Pesach, or just before Pesach that may not have taken root before 16 Nisan. This includes barley, oats and, in some places, wheat. These are forbidden until after the following 16 Nisan. If they took root on the 16 Nisan, they are permitted on the evening that starts the following 17 Nisan. This rule also applies to alcoholic beverages made from such produce: they are prohibited until after the following Pesach. Yeast derived from the process is likewise forbidden and if one used this yeast on dough even of the old produce, the dough is prohibited because of the yeast. If one isn't sure whether produce is old (yoshon) or new (chodosh), he must consult an authority.
172:3 Some authorities are of the opinion that the prohibition against chodosh only applies to produce grown by a Jew. Even if it was grown in a field belonging to a non-Jew that the Jew has rented, the produce is prohibited as chodosh. However, produce grown by a non-Jew is not forbidden as chodosh. One may rely on this opinion in a case of need. In any case, there is no such leniency when it comes to produce grown by a Jew. Many authorities differ, however, and say that chodosh also applies to the produce of a non-Jew; those who act stringently will be blessed.