Kilayim, Chapter Six, Mishnah Two
This mishnah deals with an aris grown on a terrace, and the vines are draped over a field below. Do the vines above cause it to be prohibited to sow seeds in the fields below?
1) An aris which projects from a terrace:
a) Rabbi Eliezer ben Jacob says: if a person standing on [level] ground is able to harvest all of it, [such an aris] prohibits [sowing seed in] four cubits of the field, but if [he is] not [able to do so], it prohibits [sowing seed] only [in] the [soil] which is directly below it.
2) Rabbi Eliezer says: even one who has planted one [row of vines] on the ground, and one on a terrace, then if it is ten handbreadths above the [level] ground, one does not combine with the other; if it is not [ten handbreadths high] then one does combine with the other.
Section one: If a man standing on the ground below is able to reach up and harvest the grapes from the aris, then we look at the aris as if it stood in the field itself and it prohibits sowing seeds within four cubits. However, if he cant reach up and harvest the grapes then the aris prohibits sowing seeds only directly below the aris. It will be permitted to plant in the space not directly below the aris, even if this is less than four cubits from the vines.
Section two: Rabbi Eliezer brings another rule that also has to deal with vines planted on terraces. If one row of vines is planted on an upper terrace and another row is planted on a lower terrace, then the rows combine, provided that the upper row is less than ten handbreadths higher than the lower row. In such a case the rows will combine to form a vineyard. However, if they are separated by more than ten handbreadths, then they do not combine to form a vineyard and each row is treated separately.