Gemara

(Beraisa #1): One may bring Bikurim and recite (Viduy Bikurim - Devarim 26:3-10) from the following: produce that grew on the roof, in a ruin, in an Atzitz (flowerpot), or on a boat.

Contradiction (Beraisa #2): One brings Bikurim from these, but does not recite.

Answer (for Reish Lakish): One brings and recites for produce that grew on the roof of a cave (this is like regular land), in a plowed ruin, in an Atzitz with a hole, or on a Cheres (earthenware) boat;

One brings and does not recite for produce that grew on the roof of a house, in an unplowed ruin, in an Atzitz without a hole, or on a wooden boat.

Gitin 7b (Beraisa #1): Bringing a Get in a boat is like bringing a Get in Eretz Yisrael. (People know that it must be Lishmah, and it is easy to validate it, so a Shali'ach need not testify that he saw it written and signed.)

Contradiction (Beraisa #2): It is like bringing a Get in Chutz La'aretz.

Answer #1 (R. Yirmeyah): Beraisa #1 is like Chachamim, and Beraisa #2 is like R. Yehudah;

(Mishnah): If soil of Chutz La'aretz is in a boat in Eretz Yisrael, Ma'aser and Shemitah apply to what grows in it;

R. Yehudah says, this is only if the boat scrapes the bottom of the river. If it floats (at least 10 Tefachim), it is exempt from Ma'aser and Shemitah.

Answer #2 (Abaye): Both Beraisos are like R. Yehudah. In Beraisa #1, the boat scrapes the bottom. In Beraisa #2, it floats.

(R. Zeira): R. Yehudah and Chachamim argue also about an Atzitz on pegs (e.g. a tripod).

Rejection #1 (Rava): Perhaps all hold that Ma'aser and Shemitah apply! R. Yehudah exempts only in a floating boat, since it moves. He would not exempt a Atzitz, which is stationary!

Rejection #2 (Rava): Perhaps all would exempt! Chachamim obligate in a boat, because there is no gap between it and the ground. Water is like a continuation of the river floor;

A suspended Atzitz is separated from the ground, so it is exempt!

Shabbos 81b (Reish Lakish): One may be Mekane'ach (clean himself after a bowel movement) with rocks with grass on them (the Halachah follows R. Shimon, who permits Davar she'Eino Miskaven). One who intentionally detaches the grass is Chayav Chatas.

Inference (Rav Papi): (This is not considered detaching.) Therefore, one may likewise move Parfisa (a Atzitz with a hole with something growing inside).

Objection (Rav Kahana): It is permitted for a need (Kavod ha'Briyos, i.e. Kinu'ach). Perhaps it is forbidden without a need!

(Rav Papi): If Parfisa was on the ground and one put it on pegs, he is liable for detaching. If it was on pegs and one put it on the ground, he is liable for planting.

95b (Rava): There are five Shi'urim for Klei Cheres... if it has a hole big enough for a small root to pass through, it is not Machshir seeds (planted in it, for they are considered to be attached to the ground).

Rishonim

Rambam (Hilchos Shabbos 8:4): If grass grew in a clump of earth, one who lifts it off the ground and puts it on pegs is liable for detaching. If it was on pegs and he put it on the ground, he is liable for planting.

Magid Mishneh: The Rambam explains that Parfisa is a clump of earth. Rashi explains that one is not truly liable, for Chachamim would not permit a Chiyuv Misah for the sake of Kinu'ach. His text of the Gemara merely said 'Chayav'. It did not say 'Chayav Chatas.' The Rambam did not bring the Heter Kinu'ach using a rock with grass growing on it. Perhaps he holds that it is permitted only if the rock is on pegs. He did not need to discuss it, since it is considered detached.

R. Chaim ha'Levi: The Rambam holds that even though it still nurtures (and is considered to be growing) from the ground, it is not considered attached.

Rambam (Hilchos Tum'as Ochlim 2:11): If something is planted in a Kli of dung or earth, the roots can break through the Kli, so it is as if it has a hole.

Ra'avad: The Gemara says so even regarding Cheres.

Rosh (Hilchos Orlah 3): Orlah applies to what one plants in a Cheres boat, even if it has no hole. The Yerushalmi says that roots break through Cheres. Wood requires a hole.

R. Shimshon (Orlah 1:2): Orlah applies to what grows in a boat (Rosh - if it is of Cheres) even if it does not have a hole. The Yerushalmi says that what grows in an Atzitz is liable, because the roots break through the Cheres. It says the same applies to anything planted. (Rosh - however, an Atzitz of wood requires a hole.) The Bavli disagrees.

Rashi (81b DH Hai): One is liable for moving an Atzitz from the ground to on pegs, for it ceases to 'smell' (absorb vapors from) the ground. I say that he is not really liable. Rather, it is forbidden because it looks like detaching.

Hagahos Ashri (Shabbos 8:2): Rashi holds that even when it is on pegs, in nurtures a little. Therefore, the Torah exempts for detaching or planting. If so, if one totally interrupted the nurturing through wood or a garment, he is liable mid'Oraisa.

Rashi (7b DH Atzitz): An Atzitz is considered attached (to the ground) only if it has a hole.

Tosfos (84b DH Kan): Rashi explains that one brings Bikurim and recites if the boat was of Cheres. We did not say that the Beraisos discuss wooden boats, and one recites only if it has a hole, for normally boats do not have holes, lest water enter. This is difficult, for to resolve the Beraisos, we say 'here we discuss a boat of wood, and here of Cheres.' Regarding everything else (a roof, ruin and Atzitz), we mention first the one from which we bring Bikurim and recite! R. Tam says oppositely, that Cheres requires a hole. Shabbos 95b supports this. Also, a Stam Atzitz is of Cheres. R. Tam says that a hole does not help for wood. Gitin discusses a Cheres boat with a hole. Earth clogs up the hole, so water does not enter. The Gemara here did not mention a boat with a hole, for we said so about an Atzitz, and we wanted to teach a different Chidush regarding a boat. Also, we do not want to establish the Beraisos to discuss Cheres boats, for a Stam boat is not of Cheres. Initially R. Tam explained that wood does not need a hole. In every case, the Gemara explained first the case in which one brings Bikurim and recites.

Tosfos (7b DH Atzitz): Rashi explains that above we discussed a boat of Cheres. It need not have a hole (to be considered attached) if it rests on the ground, like it says in Menachos. An Atzitz of wood is considered attached only if it has a hole. It seems that he learns from Menachos 84. To resolve the contradiction regarding a boat, the Gemara did not say that in one case it has a hole. This implies that Cheres is considered attached even without a hole. This teaches a Chidush that we did not learn from an Atzitz. This is difficult, for we say that a Pruzbul (document that empowers Beis Din to collect one's loans, so Shemitah will not cancel them) written on the Cheres of an Atzitz Nakuv (with a hole) is Kosher. This implies that Cheres requires a hole. If not, why did it mention a hole? Also, it connotes that a Stam Atzitz is of Cheres. The Rashbam supports this from a Tosefta in Shevi'is. R. Meir says that it is normal to encase Luf (onions) in an Atzitz, so it will not sprout. He supports this from "u'Nsatem bi'Chli Cheres." R. Tam says that an Atzitz of Cheres is considered attached only if it has a hole, but an Atzitz of wood is considered attached even without a hole, for it absorbs moisture more than Cheres does. Also, a Stam boat is of wood. Here (in Gitin), we could not have answered that one Beraisa discusses a Cheres boat, and the other a wooden boat, or that one discusses a boat with a hole, and the other a boat without a hole, like we answered in Menachos. When the boat touches the ground, it is unreasonable to consider it like Chutz la'Aretz regarding Gitin just because what grows in the boat is exempt from Ma'aser because (it is as if) it is in a Kli that blocks nurturing.

Tosfos (7b DH Dilma): Really, an Atzitz is considered attached. One may write a Pruzbul on an Atzitz with a hole (Gitin 37a). We establish this to be when it is on pegs. It was a mere Dichuy to say that perhaps all agree that an Atzitz is not considered attached. In Shabbos, we say that if an Atzitz with a hole was on the ground and one put it on pegs, he is liable for detaching. That is only mid'Rabanan, like Rashi explained there.

Poskim

Shulchan Aruch (OC 336:8): Even if an Atzitz has no hole, one must be careful not to move it from the ground to on top of pegs or vice-versa, whether it is of wood or of Cheres.

Beis Yosef (DH Kasav): In Shabbos (95b DH Tahor), Tosfos says that R. Tam holds that if Cheres has a hole, it is considered attached, and wood does not need a hole. In Menachos (84b DH Kan), Tosfos said that he initially held that Cheres requires a hole, but wood does not need a hole. Later, he said that a hole helps for Cheres, but not for wood. The Rosh and Tur (YD 294) hold like Rashi.

Gra (10): One should be concerned for both Perushim. It is forbidden even if there is no hole. The Yerushalmi supports Rashi. It asked incredulously, does Cheres block roots (of trees)?! The Yerushalmi was unsure regarding other vegetation. The Rambam and Shulchan Aruch rule that Orlah applies to what grows in a Stam Atzitz, i.e. even without a hole.

R. Akiva Eiger: Rashi explains that Shabbos 81b discusses an Atzitz with a hole. This connotes l'Chatchilah one may move an Atzitz without a hole, for even on the ground it does not nurture! Even if it had a hole, the Isur to put it on pegs is only mid'Rabanan. To forbid an Atzitz without a hole is like a decree for a decree! Perhaps the Shulchan Aruch is stringent due to the Safek if the law of Atzitz without a hole applies to wood or to Cheres.

Kaf ha'Chayim (52): The Shulchan Aruch (312:3) permits Kinu'ach with rocks with grass on them. This is unlike the Rambam. Here the Shulchan Aruch is stringent about Atzitz without a hole due to the Safek if the law of Atzitz without a hole applies to wood or Cheres.

Mishnah Berurah (43): Even without a hole, taking it off the ground is detaching mid'Rabanan, for it reduces nurturing, and all the more so one must be careful if it has a hole.

Mishnah Berurah (44): If one has herbs growing in a pot, he must be careful not to move it from the ground to a table or vice-versa. This is a Torah Isur!

Kaf ha'Chayim (54): One may not move them even for the need to the Atzitz or its place.