The concept of crop rotation is simple. Its the practice of not planting the same crops in the same place in back-to-back years. By not planting the exact same vegetables in the exact same spot every year, you can avoid having pests and disease continuously building up in the soil. If you move the crop, the pest or disease has no host to live off of, ideally rotate a vegetable (or vegetable family) so that it grows in a particular place once out of every 3-4 years.