I am new to growing onions. I remember my Dad bending the stems but at the place I got my onion sets they said not to. What do you do?
No reason to. Just let them do their own thing. They will lay over all on their own when the time is right.
By bending stems the vegetative growth of the stems will be curbed that will enhance the growth of the bulb since Auxin level will be reduced (due to bending of the stem).This is done only after the stem has set the flower.
"This is done only after the stem has set the flower."