Responsa for Berakhot 43:26

Regarding those who plant vegetables in their vineyards. They rely on that which was said (Berachot 22a:13) "Common practice follows the opinion of Rabbi Yoshiya with regards to kilyaim, forbidden mixtures in the vineyard, and one is not punished unless one sows wheat, barley and grape-seed all at once." They say that since the Talmud uses the term 'common practice', it seems that sowing only wheat - and even more so, vegetables - in the vineyard is permitted. Moreover, even in the land of Israel itself, planting vegetables in the vineyard is only a rabbinic prohibition, it therefore stands to reason that outside the land it should be permitted¹This is the opinion cited in Tosafot on Kiddushin 39a:12, attributed to the Ri in Beit Yosef on Yoreh Deah 296. The Meiri on Kiddushin 39a:9 mentions that "the rabbis of France are lenient on this matter.". And there are those who understand this differently. They say that when the Talmud made this comment about common practice regarding kilyaim, as well as two other examples of 'common practice' (that of following Rabbi Ilai's opinion concerning wool offering and that of following Rabbi Yehudah ben Beteira's opinion regarding immersion before Torah study) - the sage who gave all these examples of 'common practice' was worried and concerned about the people who were permitting what was forbidden. I asked [in my dream] whether we can rely on those who are permissive, or whether the law follows those who forbid.