(Mishnah): A vegetable bed that is six by six Tefachim may have five different types of seeds sown inside it - one on each side and one in the middle.

If it had a Tefach wide border that was a Tefach tall, he may plant in it 13 - three along each border and one in the middle of the bed.

He should not plant the head of a turnip in the border, as it will fill it (and make all of the species appear to be mixed).

(R. Yehuda): One may plant in the middle of the bed even six different species.

(Gemara): (What is the source to permit planting five different species?) The pasuk states (Yishayah 61:11), "Zeru'eha (its seeds)'' - meaning minimally two seeds.

(R. Shmuel bar Yasrata): From the permission for two, you can learn permission for four - just as to permit two, one must plant one species at the beginning of the bed across its width, meaning 6 Tefachim, that narrows off until the middle of the bed, so too with four different species, each one is planted across one side of the bed that narrows off until the middle, as there will certainly be a point in the middle of the bed that is empty, to be able to plant another species there, totalling five.

(R. Yona): The permission of a Rosh Tur applies when two species meet there, but here, where the middle seed is surrounded on four sides, it does not apply.