Tap on the Cash Register button in the bottom left corner of the screen to visit the General Store.
When the General Store opens, tap the top-most tab to view the Crops. Drag a chosen Crop onto your Farm, water them, then wait until they are ready to be harvested!
Note: A player can have a maximum of 6 similar Crops of each type for Land Crops.
Below are the different types of land Crops that you can purchase:
Below are the different types of Water Crops that you can purchase:
These Crops can be planted in your Water Plots once you have unlocked it: