Reference for Kilayim 5:7
הָיָה עוֹבֵר בַּכֶּרֶם וְנָפְלוּ מִמֶּנּוּ זְרָעִים, אוֹ שֶׁיָּצְאוּ עִם הַזְּבָלִים אוֹ עִם הַמַּיִם, הַזּוֹרֵעַ וְסִעֲרַתּוּ הָרוּחַ לַאֲחוֹרָיו, מֻתָּר. סִעֲרַתּוּ הָרוּחַ לְפָנָיו, רַבִּי עֲקִיבָא אוֹמֵר, אִם עֲשָׂבִים, יוֹפַךְ. וְאִם אָבִיב, יְנַפֵּץ. וְאִם הֵבִיאָה דָגָן, תִּדָּלֵק:
If one is passing through his vineyard, and seeds [accidentally] fell from him, or [seeds] have gone [into the field] with manure [that he was applying] or with [the irrigation] water, or if he was sowing [seeds] and the wind blew [the seed] behind him, they are permitted [because they were planted accidentally], [but] if the wind blew them in front of him [and he sees that they fell into he vineyard], Rabbi Akiva says, If [he found] blades [that grew from these seeds], it must be turned [uprooted, so as not to grow again] up], if ears [there are kernels in the stalks, but they have not to one third their size] he must beat them [the kernels out of the stalks], if they produced grain, they must be burnt.