Mishnayos Kilayim Perek 2 Mishnah 2

במה דברים אמורים תבואה בתבואה – grain [is mixed] with a species of grain or pulse that we said in one-fourth of a Kab per Seah, he should diminish/reduce it, but garden seeds [which are not used for food (i.e., seeds of vegetables) that were combined/mixed with grain or pulse [combine to form an amount sufficient to prohibit the sowing of the Seah].

מעשרים וארבע בנופל – from them to the Bet Seah (i.e., 50 cubits by 50 cubits/2500 square cubits) of wheat, that is to say, according to the measure of seed that they sow from them for the place that they sow in it a Seah of wheat. And the measure of the place that they sow a Seah of wheat is fifty cubits by fifty cubits but they don’t sow in it from the seeds of a garden other than a Kab and one-half because they are thin, and a Kab and one-half from them there is sufficient to sow a place that they sow a Seah of wheat. It is found that according to this calculation, that if it was mixed in one Seah of grain or pulse or rows of plants in one bed (i.e., seeds) which are one-in twenty-four of a Kab and an a half from garden seeds which is one of sixteen in a Kab, it is necessary to diminish/reduce them. Therefore, if there was combined in a Seah of grain the volume of an egg and half of garden seeds, which is one out of twenty-four of a Kab and one-half of a Kab, he must reduce it.

כשם שאמרו להחמיר – that thin seeds prohibit in a small measurement with one in twenty-four which fall from them into a Bet Seah (i.e., 2500 square cubits), such they said to be lenient for thick seeds that require many of them to sow in a Bet Seah do not forbid in a Seah of wheat other than one in twenty-four when it falls from them into a Beth Seah, such as seed of flax that requires three Seah for a Bet Seah of wheat, there is no need to diminish it until it combines with them three-fourth [a Kab] in a Seah, which means that it is taught that the flax in the grain combines one in twenty-four when it falls into a Bet Seah, and since three Seah falls from them into a Bet Seah, and we state in the Jerusalem Talmud that it is found that there is no need to reduce it until there would combine from them three-foruths of a Kab into the Seah, and such is the Halakha.