If you grow them in the Vidalia region (20 counties around Vidalia, GA), you're aok... but if you grow them outside of that area, and call them a Vidalia, you'll get into hot water. The law mainly came into existence cause Texas farmers began growing regular yellow onions and slapping the 'Vidalia' name on it, and customers would get pissed. So all the Vidalia farmers got together and got a Federal law passed that says you can only call an onion a 'Vidalia' if it's grown in our special region down here where we have sandy, loamy soil that contributes to the mild, sweet taste.