I read somewhere a long time ago that there was a shortage or just no seed to grow these food crops in most areas. Some people had a bit but were very particular who they may have shared it with. I can see how this would be a problem. Some of those who grew a few crops just had the Union come along and burn em or eat em. The lack of help in tending fields would hamper this too.
Those who did manage to grow cotton had their seed stock on hand. It wasn't easily available.
Pam