I recently read a post from a troubled homesteader who for the 3rd year in the row was trying to grow onions but was not having any luck.
There are many problems that us southern gardeners run into while planting and growing are own food. Bad soil, hot weather, droughts, and now correct seeds.
The problem is at least with onions the south and hot regions need a different type of onion then most common types.
80% of onions are what they call long day onions meaning they need a longer day then the south has. If you plant these long day types in the south you result in no or small bulbs.
1 problem is short day onions do not produce sets so any onion you plant from sets will not grow to well in the south!
Look for onions listed as short day types. Last year I had good luck with red creole onions from bakers creek
Also for larger bulbs I have found that mounding dirt around the plant as it grows helps produce larger better quality onion bulbs but not everyone agrees some report they have best success letting the bulb grow out the top of the soil.. so experiment.. mound some leave others uncovered see what works best for you!
This coming season why don't you go wild and plant a row of onions! : )
Here is a website with some short day onion seeds for sale: