Answer:
Developing industry
Step-by-step explanation:
His idea for the New South occurred after the civil war.
Before they began the civil war, the southern states were heavily reliant on slavery for their production. So when the slaves were freed by the end of the civil war, the southern states fell into economic depression.
Henry Grady's idea for the new south advocated for the investment in machinery to replace the slaves. This will gradually create Developing industry in the south and solve their economic problems.