SOW: To "sow" (rhymes with "go") is to plant something in the ground. It is what the OU Sower does, for example, planting the seeds of learning. It is an irregular verb: I
sow, I
sowed, I
have sown.
SEW: To "sew" (also rhymes with "go") is to stitch, to put together with thread.
Just to make things more complicated, there is also a noun "sow" (rhymes with "now") which refers to a female pig.