(Mishnah): If one plants two rows of squash, then two rows of pumpkin, then two rows of Egyptian bean, it's permitted. One row of squash, one row of pumpkin and one row of Egyptian bean is prohibited.

If there's one row of squash, one row of pumpkin, one row of Egyptian bean and then another row of squash - R. Eliezer permits it and the Chachamim prohibit it.

A person may plant squash and gourd in the same hole (despite the extensive leaves that grow), as long as each one bends in its own direction, with the ends of its leaves bending in their own direction - as the Chachamim didn't apply the prohibition of Maris HaAyin in cases that don't look like Kilayim.

(Gemara) (Chizkiyah): 'If one plants two rows...' This fits into the same dispute as the next Mishnah (see Menachos 53 (a)-(b) that discusses the required separation between onions and rows of gourds). The opinion there that required 12 Tefachim requires it here as well; the opinion there that required 8 Tefachim requires it here as well. (This second opinion is therefore the author of our Mishnah.)

(R. Yochanan): This Mishnah follows both opinions as all agree that 8 Tefachim suffice here. The plants being discussed here are Muksha plants (that have large leaves that extend sideways). However, the next Mishnah discusses the separation between Mukshim and onions, where it is harder to even notice the existence of the onions as a separate 'field'.

Question: How long must the Mukshim row be to be considered surrounding the inner rows (and therefore prohibit)?

Answer (R. Zeira): Learn it from a vineyard - just as a vineyard's length is at least 8 Amos, but one may only join a vine to a vineyard if it is not more than 8 Amos away from another vine, so too here, the length is the same as the separation and just as they are considered surrounding those between them only if there is no more than 8 Amos between them, so too the length of the rows is 8 Amos.

Question: According to Chizkiyah (above), R. Akiva who says there 8 also says it here (as the separation and the length are the same measurement); but according R. Yochanan (who says that they are different measurements) - what is the length of an outer Muksha plant for it to be considered surrounding inner Muksha plants?

If you say 8 (then rows that are 8 Amos long prohibit, even though an 8 Amah separation is enough to save), then it's a Kal Vechomer that an 8 Amah long rows of Muksha planted between the onions will surround if they are 8 Amos...If a Muksha plant amongst Mukshos, that you strengthened it (i.e. treated it leniently) to save it with a separation of 8 Amos, but it is surrounded in a row of 8 Amos; then a Muksha amongst onions, that you weakened it (i.e. treated it stringently) as it is saved only with a separation of 12 Amos, certainly it will be surrounded in a row of 8 Amos.

And if you say that a Muksha amongst onions that the outer row surrounds if it's 12 Amos long, certainly a Muksha amongst Mukshos will only surround if 12 Amos long?!