The Talmud records distinctions with regard to the concept of orlah, as practiced in Israel and outside of Israel. The Rambam adds one in recording the law found in the Mishnah (Orlah 1:2), which discusses one who is planting for the public. The first opinion in the mishnah is that orlah is applicable in that circumstance, while R. Yehudah exempts. The Rambam (Hil. Ma’aser Sheni 10:4) applies the obligation of orlah to one planting for the public, citing the language of the verse “and you shall plant…” (Vayikra 19:23), but adds that this is only true in the land of Israel; outside, one would be exempt from orlah. The source for this distinction is unclear, and the Tur (Y.D. 294) notes that it is not shared by the Rosh.

The Bach suggests that the Rambam is based on the Talmud’s derivation of the above verse (Pesachim 23a), “for three years they shall be forbidden to ‘you’ (lachem),” with the word ‘lachem’ including planting for the public. Since the verse begins, “When you shall come to the land…, the Rambam may interpret the context as specifically in Israel; in the Diaspora, there would be no source specifically including planting for the public. However, this is somewhat difficult, as the Rambam does not cite this derivation at all, and in his ruling refers to other wording in the verse.

R. Chaim Soloveichik (Chiddushim, Hil. Ma’akhalot Asurot, 10:15) inquires as to the nature of the law of orlah outside of Israel, which is grounded in Halakhah L’Moshe MiSinai. He indicates that a Halakhah L’Moshe MiSinai can operate in one of two ways: a) it can define the parameters of an existing concept; b) it can teach a new concept. Thus, the Halakhah L’Moshe MiSinai of orlah can mean that a) although agriculturally based mitzvot are normally applicable only in Israel, orlah applies everywhere; or b) there is a completely separate law, that of orlah in the Diaspora, that is wholly distinct from the law of orlah in Israel. R. Chaim notes that the fact that the Rambam rules that violating orlah of the Diaspora is punished with rabbinically ordained lashes (makkot mardut) is indicative of a view that the latter position is correct; otherwise, if the Diaspora version was an extension of the Israel version, the same punishments would apply.

This, as R.Aharon David Grossman (V’Darashta V’Chakarta al haTorah, III, pp. 12-14) explains, could be behind the Rambam’s distinction in reference to one who plants for the public. If that obligation is derived from the verse, it may understandably only apply to the orlah of Israel, as only that type is sourced in the verse; the Diaspora version, a seperate concept sourced in Halakhah L’Moshe MiSinai, would have no such requirement. The Rosh, alternatively, who does not distinguish, may understand the other type of Halakhah L’Moshe MiSinai to be operative.

Many acharonim (Tzlach to Berakhot 36a, Ohr Sameach, Sh’khanim 4:10, etc.) suggest a different approach, based on the statement of the Talmud (Berakhot 36a) “all who are lenient [on orlah] in Israel, the halakhah is like them in the Diaspora.” Since the issue of planting for others was disputed in the mishnah between chakhamim and R. Yehudah, it can be understood that the Rambam applies a stringent rule to Israel and a lenient one to the Diaspora. (However, as R. Grossman observes, this would not explain the Rosh, who does not distinguish, yet still recognizes the concept of “all who are lenient…”, as evident from his code to Berakhot, 6:4).

The Ran in his commentary to Kiddushin (39a) states that the reasoning behind “all who are lenient…” is the statement of the Talmud there that an indeterminate situation of orlah (safek) is permitted in the Diaspora when it would be forbidden in Israel. Since any minority disagreement is enough to generate a safek, the halakhah will always follow the lenient view in the Diaspora.

As acharonim explain (see B’Ikvei HaTzon, p. 58 and p. 103; Kuntreisei Shiurim to Kiddushin p. 238), this reflects a classification found in a handful of halakhic concepts that assigns a status only when it is definitely called for and known about. Absent such certitude and awareness, the status is completely inapplicable. Thus, a safek is permitted not only because of the normal rules governing that situation, but because the status is simply not given at all. Thus, as the passage in Kiddushin indicates, one can feed orlah (in the Diaspora) to one who is unaware of the status, as for him, it is permitted. Other areas possibly included in this classification are mamzerut (see Kovetz Ha’arot, 58); aveilut (see Moed Katan 20a, and Yoreh Deah 402:12); and eiruv (see Eiruvin 46a).

However broad the latitude is, incorporating even very unlikely possibilities into the definition of “safek”, there may be some limitations. R. Hershel Schachter (B’Ikvei HaTzon, 18, based on Kehilot Ya’akov to Berakhot) notes that the status may not apply to a dispute where the two sides are clashing over what one individual is reputed to have said (rather than each offering his own opinion), because one version must be wrong in that case, and thus the rule “These and Those are the words of the living G-d” (Eiruvin 13a) cannot be applied (see Rashi, Ketubot 56a). Others suggest (see Resp. M’kaddshei Hashem, I, 73, in D’var Tzvi, 9) that the rule would not apply to disputes between Beit Hillel and Beit Shammai, in instances where the halakhah has decisively rejected the view of Beit Shammai.

The Tzlach (Ber. 36a) asserts that if one assumes that “kedushah shniyah lo kidshah l’atid lavo” then even the orlah of Israel is, in contemporary times, of a status with the orlah of the Diaspora. This opinion is critiqued at length by R. Shmuel Rozovsky in his Zikhron Shmuel (#12).