Name: greene Savannah, GA (Sunset 28) (Zone 8b) I have no use for internet bullies!
I am only guessing without a photo but could your soil be deficient in lime? Broccoli and other Cole crops can develop club root (due to a soil born fungus) and fail to thrive. I was always taught to add extra lime to the soil to keep the Broccoli healthy.
Sunset Zone 28, AHS Heat Zone 9, USDA zone 8b~"Leaf of Faith"