growing onions

My grandmother Powell grew onions. They only used what they raised never buying onions. I have raise onions most of my adult life and the bulbs never got larger and I read on the internet you should pull all the dirt away from the onion bulb while it is making bulbs and I remembered grandma's onion bed and how the bulbs would have all the dirt pulled away from the bulbs with only the root being in the ground. this year I am going to try pulling the dirt away from the bulbs and see if I can grow onions like grandma did.