- Hadash – grain from the new harvest that cannot be eaten until after the Omer sacrifice is brought on the second day of Pesaḥ.
- Orlah – fruit that grows during the first three years after a tree is planted
- Kilayim – forbidden mixtures in planted fields and trees.
The Gemara explains that each of these apply in the Diaspora for different reasons. Hadash is biblically forbidden (see Vayikra 23:9-14), orlah is a halakha and kilayim is forbidden mi-divrei soferim (on a rabbinic level). In explaining the meaning of the term halakha in this context, Rav Yehuda quotes Shmuel as saying that it is halakha medina, while Ulla quotes Rabbi Yohanan as saying that it is a halakha le-Moshe mi-Sinai (an oral tradition passed on from Moses at Mount Sinai).
The explanation brought by Rav Yehuda in the name of Shmuel is not very clear. Rashi suggests that it was an accepted tradition; others say that it was done following the directives of the rabbinic leaders of that time. Tosafot Hakhmei Angliya explain that it means that it was accepted in some Diaspora communities, but not in all of them.
The rule of greatest concern here is that hadash is biblically forbidden in the Diaspora. In fact, for generations it has been common practice among Jews in the Diaspora to be lenient with regard to hadash. The Rema argues that in most cases the possibility that grain arriving in the marketplace is hadash is a sefek-sefeka – a “double doubt” situation where one can be lenient (i.e. the grain may have been from last year’s crop, and even if it is from this year’s crop, perhaps it was planted before Pesaḥ).The Baḥ and the Taz both present different approaches explaining the accepted leniency, raising questions about whether we follow the position presented by our Gemara and even if we do, whether we can follow the opinions that it would only apply to grain that is grown in Jewish-owned fields.