Parashas Eikev · Passuk 11:10
For the land that you are about to enter and possess is not like the land of Egypt from which you have come. There the grain you sowed had to be watered by your own labors,dby your own labors Lit. “by your foot.” like a vegetable garden;
Torah Temimah points to Shabbos 85a.
TT lemma: כגן הירק.
English: “Like a vegetable garden.” It was taught: How wide is a furrow? A tefach, as it is written, “and you water it with your foot like a vegetable garden.” How much is a foot? A tefach.
Custom (measure of a furrow from “with your foot”)
The irrigation image supplies a tefach measure used in the laws of mixed plantings.