Shabbat 85A

וקים להו לרבנן דחמשא בשיתא לא ינקי מהדדי.

And the rabbis have an accepted tradition that 5 seeds in a 6-handbreadth space do not draw sustenance from one another.

ומנלן דהא דקים להו לרבנן דחמשא בשיתא מילתא היא? דאמר רבי חייא בר אבא אמר רבי יוחנן: מאי דכתיב: ״לא תסיג גבול רעך [אשר גבלו ראשונים]״⁠ — גבול שגבלו ראשונים לא תסיג. מאי ״גבלו ראשונים״? אמר רבי שמואל בר נחמני אמר רבי יונתן: מאי דכתיב ״אלה בני שעיר החרי ישבי הארץ״, אטו כולי עלמא יושבי רקיע נינהו?! אלא שהיו בקיאין בישובה של ארץ, שהיו אומרים: מלא קנה זה לזית, מלא קנה זה לגפנים, מלא קנה זה לתאנים. ו״חרי״⁠ — שמריחים את הארץ. ו״חוי״, אמר רב פפא: שהיו טועמין את הארץ כחויא. רב אחא בר יעקב אמר: ״חרי״⁠ — שנעשו בני חורין מנכסיהן.

The Talmud asks: And from where do we derive that when the rabbis have an accepted tradition it is a substantial matter, meaning that the tradition is reliable? R' Ḥiyya bar Abba said that R' Yoḥanan said: What is the meaning of that which is written: “You should not cross your neighbor’s border, which they of the old times have set in your inheritance that you should inherit” (Deuteronomy 19:14)? It means that you should not cross the border that the early generations set, establishing the parameters necessary for each plant. The Talmud asks: What is the meaning of the phrase: The early generations set? R' Shmuel bar Naḥmani said that R' Yonatan said: What is the meaning of that which was written: “These are the sons of Seir the Horite who inhabit the land, Lotan and Shoval and Zibeon and Ana” (Genesis 36:20)? And is everyone else inhabitants of the heavens, that it was necessary for the verse to emphasize that these inhabit the land? Rather, it means that they were experts in the settlement of the land, as they would say: This tract of land that is the full length of a rod is fit for olive trees; this full length of a rod is fit for grapes, this full length of a rod is fit for figs. And the members of this tribe were called Horites [ḥori] since they smelled [heriḥu] the earth to determine what is fit to be grown there. The allusion is based on a transposition of the letters ḥet and reish. And in explanation of why the early inhabitants of Seir were called Hivites [ḥivi] (see Genesis 36:2), Rav Pappa said: Because they would taste the earth like a snake [ḥivya] and determine what should be grown there according to the taste. Rav Aḥa bar Ya’akov said that they were called Horites [ḥori] because they became free [benei ḥorin] of their possessions when the children of Esau drove them from their lands. Their primary name was actually Hivites.