A plantation is a large agricultural property dedicated to planting a few crops on a large scale. If you dream of having 3,000 acres to raise cucumbers on, then you have dreams of a cucumber plantation.
Plantation doesn't have to only mean massive single-product farms. A small grove of trees is also called a plantation, but usually when we use the word we mean the big farms. Surely you've heard of southern plantations before the Civil War that raised cotton and tobacco with slave labor. In Latin America many international companies own banana and coffee plantations.