You may want to check for root rot. Corn needs very little moisture. I grow corn in my fields for silage and any place where there's a low area and has a high water table, the plants usually only grow to about 1/2 height. The plants where it's high and dry do the best. You could try cycling your grow bed less often....maybe once per 2-3 hours....or longer?
However, I have seen one system that had corn in it, but I'm not sure how they did it.
Don't give up on it! Half the fun is experimenting! ;-)