There are many plantations with "Oak Alley" in their name, and each had their own specific agricultural focus based on their location, soil type, and the time period they were active.
To provide you with a specific answer, please tell me:
* Which specific plantation are you asking about? For example, "Oak Alley Plantation in Louisiana" or "Oak Alley Plantation in Mississippi."
* What time period are you interested in? The crops grown might have changed over time.
Once you provide this information, I can help you find out more about the crops they cultivated.