In Civ 5 my workers won't build a plantation. Where and how do they do that?
And yes, I do have the Calendar technology. I tried doing it in a grassland with no hills, and it is my territory.
Solution 1:
Plantations are only for improving the following Resources: Spices, Dyes, Cotton, Silk, Incense, Wines (Luxuries), Bananas, and Sugar (Bonus Resources). Having the tech allows a worker to build a Plantation on these resources, claiming them and adding them to your trade network.